It is widely regarded to focus all of your attention on to one specific affiliate system to earn any income online from, as getting distracted by other affiliate earning systems will get you nowhere.
So if it's Ebay or Amazon affiliate promotions, then just concentrate on these with all of your time and effort.
Always plan and maintain a schedule of continual promotional campaigns for your concentrated method and don't ever stop, because to stop would allow others to get in before you as the action takers, so build on top of what you know!
Learn everything about affiliate marketing through the many forums on affiliate networks and other specific affiliate earning programs
Finding or writing content can take a little effort, but it's worth it to set your niche up as the premier niche for that market with valuable niche content