Testing for Adwords

you can use adword tool of google adword and test your cammpaign. But you should have an active account

one way you can test to see if a problem with your landing page is to change your destination link directly to your product page using your affiliate link still of course. bypass your landing page and see if you get any sales. you'll need to give it a couple of days to see if there is a difference in sales or no sales. if no difference. then perhaps it is your landing page. I have found that if you do not research on what makes a good landing page, a good ad or even a good keyword list, then adwords can be a very expensive and frustrating trip.
you can test out your ads by making a variation of each ad in your ad groups and change out the headline. watch for a couple of days to see which ad in your ad group gets the higher clicks. the more attractive ad will get more attention. set your campaign to rotate your ads evenly. another train of thought is as soon as you see which is the winner, turn off the rotate switch to show, best performing ad, If you havent already pay for some education on PPC. It can be daunting. PPC Classroom Brandable Affiliate Report is pretty good.
best of luck..keep learning and never give up!

it is not that expensive then the best way I find is to test results yourself. Learn some basis about adwords and then you'll be able to set some of the options there. Anyways there are more advices given by expert companies that you should check out

That has proven to be very useful, I started rotating ads and tested the landing page at the same time! Thank you for the warning there jwill, I have found a tool to group keywords and I noticed they are not very well organized, and that there is a huge flaw. Will let you know how it goes, thanks a lot.