New Website, Need HELP!

First of all, I'd like to thank everyone who has contributed to making BHW the forum it is today. I learned a lot in the past couple of months. Because of you guys, I have gathered up the courage to start a small internet business and a couple of months down the road I have 3 small businesses that are growing every month.
My latest one is a website that sells only 1 digital product. The website is built on the open ecommerce platform OpenCart. I have purchased a few extensions for it and have got it down to my liking. It's been roughly a month and the site has over a 100 hits via search engines and a lot more through PPC campaign. I bought the Backlink Massacre service on here and I saw my Alexa rank increase a bit. Sales, clicks, and searches went up slightly, but now they are leveled off to their previous levels. Since This website has been up for a month or so, I don't have a large enough data pool to determine if the links were in fact the cause of the small traffic increase.
Now I want to move into white hat SEO and rank my website as naturally as I possibly can. What would you guys recommend that I do every day to move up in ranks? Please note that I am a novice when it comes to website ranking. I have a decent knowledge of HTML, PHP, CSS, but I spent most of my time online building my ebay/amazon business. Any help at all would be greatly appreciated!

If you are socially active ex:facebook, twitter etc. Post your products there and in tern you create a backlink. Maybe have sales on your products. the sky is the limit with this, if you have a product that sells. Any sales yet?

It's a service, really. Not a digital good. And yes, I have 14 sales to date and in terms of my PPC campaign, I'm in the green zone. I'm working on gatherting data to see which keywords convert first and then I'll focus on them. How would you recommend that I rank for a certain keyword if I can't write blogs on the website?
I have a facebook page, a blogspot that I will start writing a blog or two per day, and was thinking about making a YT video to advertise the service.

If it's a competitive niche, it's likely better just to hire a SEO firm if you don't know anything about SEO...otherwise if it's less competitive, you have room to learn while still giving yourself small gains...but regardless, no real strategies can be given without knowing anything about your business.

I guess it's a competitive niche, but I figure that if I'm getting direct traffic from Google/Yahoo and have sales, I must be doing something right. An SEO firm is out of my budget at the moment, but I will definitely look into that in the future. Thank you for your suggestions so far. Anyone have a free/cheaper alternative at the moment?