Thirsty Affiliates tracks, cloaks, and categorizes your affiliate links. Once you’ve signed up for your program(s) grab your affiliate links and add them to this plugin. This can take time if you will be linking to multiple pages on your affiliate’s website (which in many cases, you should). The pro version comes with statistics but I don’t even use it and I’m quite the analytical person.
On one hand, long and ugly affiliate tracking links are a straight giveaway to people that you want to sell them a product (and people may be uncomfortable clicking on them). Therefore, making your link shorter and "nicer" looking will it give a more professional appearance. One of my favorite plugins for making links look "pretty" is the Pretty Links WordPress plugin.
One of the key elements to success with affiliate marketing is picking the right products to promote. They could be digital information products, memberships, physical products, online services… there are many industries that use this model. When promotiing to your target market, you may be promoting one or many of these different types of products as an affiliate.
But I think the biggest deciding factor in this, goes back to the site as a whole and all of the other posts. Are the genuine? Is the blogger constantly trying to push products? I’d like to think I’ve been doing this long enough that my audience knows I’m not out to make a quick buck – and I think even relatively new bloggers can prove this based on their other content.