I have some background in html design, and some history with playing with affiliate marketing. A friend of mine does PPC and he's been helping me with some tips. I started out about a month and a half ago.
I'm currently averaging about $150/day (some days are crap, like today, others can go as high as $300+) doing PPC to landing page to offer using CPA free trials. I've had some ups and downs, but I have to say this was amazingly 'easy' relatively speaking, considering the short amount of time that took to reach what basically could replace a full time job's salary!
I'm still not feeling very secure in it, as I'm running only 3 offers, but looks very promising! Here's the formula, and it's not rocket science:
1) talk to your affiliate managers as far as what offers are hot and converting. You do not want to start with an offer that you have no idea if it sells. Establishing a good relationship with them never hurts. I'm signed up with a bunch of networks, but I'm currently working with Lidango.com. Their payouts are pretty impressive compared to some of the bigger players.
2) once you have an offer, go to google/yahoo/msn and search for keywords that are related to the niche. See the landing pages and ad types that are showing up on the results. Build something along the same lines.
3) keywords - this is where I think people will have the hardest time. You need to be willing to spend some money to test out keywords. Use tools like the adwords keyword tool, and words that come to your mind as starting points. Let those run to about 1.5 times the value of the revenue of the CPA. So for instance if you earn $30 per CPA, you have to be willing to run a keyword up to $45 or so. You can see how if you have 50 keywords, this could amount to 50*$45=$2250! so you *have* to have some budget to go with at first otherwise you're not going anywhere. Hopefully you will see some sales generated by some of those keywords sooner than later.
4) So now you have offers that you know are converting for someone else. You have ads and landing pages formats that other people are using (a tool like PPC Bully or Google Cash Detective can help you with this, but I haven't used them personally). Once you have some sales, test everything. Bump up bid prices for the keywords you're getting success with. If the network allows for pixel tracking, that is also helpful, as you'll be able to see the revenue and costs right on your adwords/yahoo/msn interface. Using a tool like tracking202 also can achieve this.
Hope this helps. This is the exact process that has worked so far for me. I'm feeling pretty confident that I can boost this to $1k/day, but we'll see, I'll keep you guys updated.