Rather than buy a (most likely) generic template on WordPress, since the site is a single page, take the first 10 or 20 sales and invest that money in paying a

Rather than buy a (most likely) generic template on WordPress, since the site is a single page, take the first 10 or 20 sales and invest that money in paying a designer to design that single page site as good as possible for further conversions. Also, don't link in the same tab to your blog posts, you are taking people away from the chance to purchase, and they will typically not be back (there is probably a little higher chance because the market is developers that they will remember to come back and purchase). You should at a minimum, open the links in a new tab. I definitely second the email list, sit down and write up 52(? more/less?) short "tips" and put people that sign up on an autoresponder that emails out every week, that includes a way to come back and purchase in each email. Obviously leave a way to unsubscribe, and keep track of who purchases and put people who have purchased on a slightly different list (can still send the tips, just don't push the sale anymore).