listed in google and yahoo - now what?

ok, here's my lame anti-seo story. i promote an affiliate site and bought the .org domain name as one of their sites. i put a simple htaccess meta-refresh on it pointing back to my aff id. that was the extent of my seo effort! so if you visit my site you end up on theirs and i get credit. they don't seem to mind either (although i heard it was against their TOS).

a few weeks ago i noticed a bit of traffic coming from yahoo and google. somehow the bots found me and listed my .org site in the serps. i'm in the top 3 positions in the serps believe it or not. it was no big deal - a couple of clicks per day.

but the traffic i do get from the serps is highly targeted and really converts! today i got $50 with only 5 clicks so far! so obviously i've been ignoring the potential with this site here and would like to make a better effort at seo.

my question is what should i do now? i'm already in some of the serps - what can i do to make it into more listings? where should i go to get started with seo? do i just make doorwaypages that are highly targeted to specific keywords? or will doorways get me banned? i need some real advice here! i'm a complete noob at seo too so feel free to state the obvious!