Ask yourself why people are coming to your blog, seek out the strengths and weaknesses of the blog and choose programs according to the strengths. Try to figure out what the intention is of the people who are coming to your blog. Do they come to read and post or do they just browse and leave. Choose products that are fun and interesting. If they are boring, no one is going to buy anything. Make sure the programs are practical. If you have a blog on pets, they use affiliate programs on pet toys or pet food, pet owners always are in need of food and toys.
Placement of the affiliate programs is very important. If your blog gets more readers in a certain area then place the ads there. Place them where the bloggers are going to see them. Try to keep the affiliate programs visible to all readers. This may have to be done by trail and error. If you see that the programs are not working in some places but are working well in others then you may have to do some rearranging. If you see that ads are not doing so well, then it may be time to change them. You are not committed to keep the same products, if something isn’t working then change it around. It can only help you in the end.