I'm sure that everyone have their own strategy (and that's perfectly normal because different niches and keywords require different strategies). But in general, building links should follow these best practices....
1. only build links to pages / URLs that are indexed. I never tested if non-indexed pages with backlinks will index in the future or whether google consider them shady, but why risk?
2. if the pages / URLs have been indexed then you'll want to build links based on these tips...
2.1.... are you in a tough niche (debt elimination, web hosting, SEO, travel, illnesses and conditions, fitness, business, banking, CBD, loans, insurance, gambling, lawyers, etc.)? If yes, your most, and best links should go to the homepage because the domain's authority plays a huge role in tough niches. Of course, you will still want to save some of your best links for inner pages, but in general, most of your best and most powerful links should be reserved for the homepage. How many should be reserved for the homepage exactly? There's no answer to this, experienced SEOs usually go with 60-40 or 70-30 ratio (60% of their best links pointing to the homepage, while the other 40% being split up between various inner pages that you feel / know need a boost) but you can adjust these numbers to suit your budget and strategy;
2.2... are you in a not so tough niche? Then you will probably want to split your backlinks 50-50 while also keeping your site's structure and navigation, its topical authority and its technical SEO (easy crawlability, no 404 pages, no broken links, etc) in check, as well, because in these niches with moderate competition I noticed that all of these things (onpage SEO, technical SEO, site's speed, structure, cleanliness and topical relevance, etc) matter and add up, and can be as important as backlinks are for the tough niches when they're added together...
2.3... are you in an easy niche? (note: I can't think of any easy niche at the moment, but if you do your keyword research properly and acquire a bit of SEO experience you'll be able to spot these niches before you finish your keyword research. Now, granted, easy and easily approachable niches are pretty rare when compared to the other niches, so you'll probably sweat a lot, and spend a good few hours / days on uncovering these easy, untapped niches, but when you find one of these golden nuggets it's sooo worth it. You're gonna bank hard in those niches, all alone, for years... or until another keen SEO like you sweats a lots and finds the same niche and jumps in, creating competition for yourself lol)
So anyway, in these easy niches you don't even need backlinks usually. Just write a good piece of content that properly addresses the intent of the keyword(s) you're targeting, and you'll be fine. Good site structure and topical relevance also helps in these niches, as well so make sure you pre-plan the structure of your site before you even write your 1st article as this will facilitate your SEO efforts along the way
Regarding how to build links, follow these best practices (which are actually mandatory in some cases, not just best practices):
1. if your site is new and / or doesn't have backlinks yet, start off slowly (few backlinks a week) and increase that number gradually as time goes on and as your site grows bigger (has more content, more backlinks, and higher DR). Drip-feeding (or link velocity as experienced SEOs like to call it) is a pretty big deal for new sites and for sites without a lot of backlinks... actually, RDs (Referring Domains), not backlinks...
2. if your site is established and / or already has a lot of RDs... well, I'm assuming that you already know how to build links if you have an established site with lots of RDs
But, just in case (that someone else had done the link building for you and you're now forced to do it yourself for the first time), just take a look at the number of links that have been acquired by your site, and over how many weeks / months, and stay within that average. For example, let's say that your site is 2 years old and has 388 RDs, but all 388 RDs have been acquired in the last 6 months only.
Well, in this case you would divide the 388 RDs by 2 years (so, 24 months, or 96 weeks) and the result (which is roughly 16 RDs acquired per month, or roughly 4 RDs per week) will give you the weekly / monthly average of backlinks that you can build while staying safe from google's preying eyes...
NOTE: don't just build an EXACT number of links, each week / month, like a maniac because this will create an obvious and easily identifiable pattern by google and your site will tank hard and irrevocably! When I recommend that you stay within the historical averages of your site I mean build few or more links than the average, and vary these numbers as much as you can while still not creating obvious spikes / patterns. Just use your common sense!
As for types of links you need to get, in general quality PBNs, quality guest posts, and quality niche edits / link insertions are the best types of links on the market today. Which are also the most expensive, by the way, so if someone offers to build you "quality PBNs for $1" simply refuse him / her because he/she is obviously a scammer, or doesn't know what they're doing. Backlinks that put food on your table don't cost $1, sadly...
Quality PBNs = backlinks on the homepage of quality websites...
quality PBN sites = sites that... 1) are indexed and rank in google... 2) get traffic from google (optional, but recommended)... 3) sites that have low OBLs (Outbound Links, which are links that point to other websites like yours. In general, you want the OBLs on the page giving you the link to be under 10, or under 20 if the website giving you the link is big / popular, as low numbers of OBLs means that the link juice / authority that flows into your site is decent)... 4) have a decent amount of RDs (after all, a lot of quality RDs is what gives power to that PBN, which is what furthermore gives power to the backlink that you're paying more than $1 for)
Quality guest posts = articles that you write (or someone else writes for you) and then you publish on quality sites
quality guest posting sites = sites that... 1) are in the same niche / industry as you (preferred, but not mandatory)... 2) are indexed and ranking in google (in general you want sites with google traffic as much as possible, if those sites are able to rank in google and get organic traffic it means that the owners of those websites know what they're doing, and will probably care about your guest post)... 3) have decent number and quality of RDs (again, the goal of getting backlinks through guest posts is getting a good chunk of the authority of those websites, but if those websites' authority / DR is low because they don't have enough quality RDs point to them.... well, what's the point of getting a guest post from that site then?)
Quality niche edits / link insertions = backlinks from articles on quality sites, with those articles already being indexed and ranking in google, and getting traffic (either from google or from other pages on the site, via internal linking).
Normally, niche edits are way better than guest posts (because they already rank and get traffic and some of that traffic will click through to your backlink to visit your page, which is a double win for you, which is why niche edits are usually more expensive than guest posts), but like I said, they're also more expensive, so if you somehow manage to get a niche edit from an aged article on Cosmopolitan (just an example) then be expected to pay mindboggling amounts of $$$. I've seen some prices charged by an SEO agency a few months ago where a link on Cosmopolitan was costing $30,000 (yeah, that's $30k !!!)... and I think that wasn't even a niche edit link, it was a guest post lol....
So, be wary of what you'll be expected to pay for quality links
Last but not least, some things that I forgot to mention and which are also important, is the d0follow / nofollow links. Nofollow means that the link will not pass link juice / authority through to your website, and if you'll ever be offered "cheap quality links" for $1-2 first things that you should check about those links are.. 1) do they come from link farms (link farms = sites built specifically to sell links to anyone and everyone on the planet)... and 2) are the links do-follow or noffolow?
If they're nofollow ignore the offer, if they're d0-follow check all other metrics and best practices that I explained above....
Also important (and obvious to most advanced-expert SEOs but little known to newbies) is that links that are either free to get, easy to get, or both, are usually worthless. I'm talking about these types of links here....
- article directories
- wikis
- bookmarks
- blog comments
- web 2.0s
- link directories
- etc...
Basically, every link building opportunity that you and me have access to, google will shit on as soon as they figure out that mere mortals have access to them. I'm not the one making these links worthless, and believe me that it bothers me as much as it probably bothers you that these links that we all have access to don't amount for any effort that we're putting into creating them, but it is what it is and as long as we live under google's monopoly and hegemony we need to play by their rules or stop doing SEO. That's how it is...