Know when (and when not) to use Viglinks and Skimlinks. If you applied to an affiliate program but were denied, you might be able to still be an affiliate for that advertiser through a secondary affiliate program like VigLink or Skimlinks. Basically, they themselves are affiliates and will split their affiliate commission with you if you put their affiliate link in your content for an advertiser. Obviously, the commission rate is lower for you in this case, so if you ever are accepted into the advertiser’s affiliate program directly, immediately switch from using VigLink / Skimlinks affiliate links to your own.
Hosting – I suggest joining the WordPress Hosting and WordPress Speed Up Facebook Group and see what real (unbiased) people are saying about hosting. SiteGround was #1 in multiple Facebook polls and #1 in most Facebook conversations (this one too). People who migrate usually see significant load time improvements especially if they’re currently using Godaddy/EIG. I use their semi-dedicated GoGeek plan which comes with 4x more server resources than regular shared hosting (#1 factor in WordPress Optimization Guide) and have <1s load times with 100% scores in GTmetrix/Pingdom. SiteGround also does free migrations.
The problem with affiliate marketing, like many other home business options, are the so-called gurus and get-rich-quick programs that suggest affiliate marketing can be done fast and with little effort. Odds are you've read claims of affiliate marketing programs that say you can make hundreds of thousands of dollars a month doing almost nothing ("Three clicks to rich!"). Or, they suggest you can set up your affiliate site, and then forget it, except to check your bank deposits.