If you are a beginner in this particular field I suggest that you read further about the problems I have encountered with affiliate marketing and the lessons I have learned from it.
When I ventured into an affiliate program approximately two years ago I never thought of the possibility of reading online marketing reviews nor to do an in-depth affiliate marketing research on the web.
Not doing so have cost me a lot of time and money.
For me and many other new internet marketers the step of finding the best programs in affiliate marketing boiled down to trial and error.
What I have learned the hard way was that the trial and error method of finding the best programs in affiliate marketing is not the most time and cost-effective way of doing things.
If you take your time and follow the next steps you should be able to distinguish between good and poor affiliate programs:

• Make an in-depth research on an affiliate program that you are interested in.
  
• Make contact with the merchant of the affiliate program to sort out any uncertainties.
  
• Get the opinions of experienced affiliate marketers about the particular program.
  
• Identify between honest and dishonest affiliate programs.
  

The most common stumbling block in affiliate marketing for me was how to recognize a good affiliate program from a bad one.
It is very important to do an in-depth research online before joining an affiliate program.
I usually examine the terms and conditions of the agreement of the merchant's program very well and make notes of everything which is not clear to me.
I am careful of an uncaring affiliate manager or one who does not respond to ones issues.
I am also cautious of internet affiliate companies that use their customer service to handle affiliate matters.
Having a successful and helpful affiliate manager is an indicator to me that the relative company is a good one and cares about its clients.
My policy is not to depend on an affiliate manager that only show the impressive side of his particular program.
Even if it's a good program there is always also a downside.
Irrespective of how small that downside information is I also need it to make an informed decision.
I usually ask the program manager to forward me the contact info of a few of their leading and experienced affiliate marketers.
If it's a good company they generally are pleased to do so.
I ask the affiliate marketers what their experience with the merchant and his program under consideration has been.
Honest affiliate reviews that supply the benefits and drawbacks are considerably more valuable than those that only give information about the good capabilities of a particular affiliate program.
My advice therefore to you is to do an in-depth research on every affiliate program you are interested in, in a professional and responsible way.
There are definitely no guarantees but by using these methods should in a way help protect you from unscrupulous merchants, or at the least to lessen your vulnerability to poor programs.