There are many affiliate networks out there but for a professional blog ShareaSale is the best one. Here are the reasons:
1) It has more than 3700 active programs for which you can apply.
2) Out of that about 300 are related to pay per lead. That means for these programs you still make money whether someone buys a products or not. They just have to register for the product and create an account.
3) There are more than 85 products which are solely related to WordPress themes, plugins, tools and resources.
4) It has a collection of some of the best converting programs like that of Genesis, Thesis, Rocket themes, etc.
5) Real time statistics: The moment someone clicks on your affiliate link you can check that in the reports section. The reporting is 100% real time and there are very few affiliate networks who have this kind of solid reporting. My personal favorite is Today at a Glance report where you can see the clicks and earnings for a particular day.
6) International Network: It is an international network and it supports almost all the countries.
7) Easy Affiliate Approval: They are not very strict when it comes to affiliate approvals. Just make sure you have a decent performing blog and your blog will be approved.
8) Timely payments: Once you reach $50 they will pay you on the 20th of the next month.
9) Multiple payment options: You can get the affiliate payment by checks to your postal address. Also, they provide direct deposits to the bank accounts in many countries.
10) Easy to create custom links: You can easily create custom links for the products as per your requirements. You can also enable click tracking to track the performance of the custom links.