You can search a bit and find many posts regarding your question.
They are so many ways for make backlinks
Make blog comments
Article submission
web 2.0 submission
Socialbookmarking
Do High PR D0f0ll0w Auto Approved Blog Comments ...
Guest posting and article submission.
Write some great content, then email the owners of some sites in your niche and ask if they would like to trade links.
Does article submission have the same effect prior to g updates?
How many articles per day?
And which article websites works best?
do web 2.0,social bookmarking and link exchange with other blogs.Its more effective than any other.you will get permanent link back to your site.it never dies and will bring traffic for long time which help a lot in improving rankings
Yes.
It depends on many things, but up to 5 articles per day should be safe.
The ones with high PR, with authority, with good Alexa rank, and so on, like Ezine for example.
I've personally only done this a few times. It worked well though, but partly because of my niche I think: I picked a niche that people wouldn't expect to be monetized, but I found a way. In one case, someone actually emailed ME first and asked to trade links.
I think the finest way to link build is to have consistency in finding authority and high pr ranking sites that are related to your niche. realize diverse link building techniques with quality in order to get reputation in search engine.