Don't let your business be dictated to by the perceived need to outdo others! Set out your stall so you achieve the standards that you believe your niche wants NOT what others may think they want. Your 'competitors' may not even be making a profit, so why let them tell you what to do? Experts are always talking about beating the competition or spying on them, but the Internet is so vast that even huge businesses have got lots of room - unless they're in very small niches.
Assuming you're in a big enough niche, you will almost have the world at your feet in terms of choice. If you're going to be selling affiliate products you'll have more than enough to be able to pick the best for your potential customers - and you OWE it to them (and yourself!) to select the best for them. If you just select the products that everyone else is promoting because you want to keep up with the competition, you'll only be one of a crowd of people whose business ideals are completely unknown to you!
So, if you think about it, you're not deciding your businesses policy, that anonymous crowd is! That's really no way to start in business - just following the crowd!
Even if you're very inexperienced in business in general, you must know a good bit about your niche, otherwise, why did you choose it in the first place? If you know what your niche is all about, it follows that your judgement should be at least as good as the next guy's and if you're going to be a real professional you should easily be a couple of streets ahead of most people! So why follow them?
I'm not saying that you can't learn by observing what others in your marketplace are doing. But if you regard them as competitors, you could be motivated by trying to beat them, rather than trying to learn from them. For example, you may really admire the way a particular site looks but feel that it's let down by ads for low class products that you wouldn't personally touch with a barge pole. So you could adapt their style to your business but silently wish them good luck with the tacky products - they're welcome to them!
This is only a brief look at the subject of competition - deliberately so, because I seriously question whether anyone who falls into that category is really worthy of your attention. By all means learn from others - even what NOT to do is well worth knowing but let competitors COMPETE, if that's what they want to do do, while you get on with making money!