First of all, I don't make a lot of money at affiliate marketing, but I make enough to scrape a part time income at it to know that a concentrated effort is way better than a half arsed effort. The ways to really be good or even exceptional at affiliate marketing is to really knuckle down and act professional and business like and be methodical when it comes to affiliate marketing, by covering all of your bases you will be in a better position to make money as an affiliate, simple as that!
Many of the top affiliate marketers have their sights set on multiple affiliate campaigns thatbring in one time affiliate commissions or a collection of one time, recurring and CPA commissions which do all add up to make a good chunk of change.
I remember seeing one top affiliate who showed you all of his computer dashboard with all the files of each promotion that he was doing and he had hundreds of different promotions going on at the same time and this made him a super affiliate, because he was spreading his efforts on many other niches too, which made him more money, but I bet that he spent a considerable amount of time setting these up and also he must outsource some of his promotion work by now.
So if you're thinking of getting into affiliate marketing, do treat it like a business, because others do and they are good at it, I could be too, if I didn't draw too much