For the beginner online marketer, one of the most basic and easiest tool to learn is the Google Keyword Tool. This tool allows you to input search terms, and see how many people search for it, or search for the general idea under it. This is how you find a good niche and website name to sell on. Until one gets extremely good at search engine optimization, it's all about
1. Find keywords that has a decent amount of searches, but not too many so that SEO competition becomes impossible. A range of 5000-10000 is usually manageable to get ranked top of Google for, while still bringing in good amounts of visitors.
2. Find keywords that have websites that aren't terribly competitive. For example, the search term "Beds for dogs" may only have 3000 global searches per month, but if the beds for dogs webhosts are randomly SEO gods, then you know to stay away. There are various methods to analyzing this.
Anyway, I hate long entries, so I'll stop here. Thanks for reading.