So creating a logo that is graphically appealing is super important. When it comes to creating these logos I have found that it is useful to stick to a few simple guidelines.
A logo should not have more than two different fonts, and three different colors. These limitations help to keep a design simple and easy on the eyes. Overly complicated designs can get confusing or overwhelm a customer. These rules are also useful because a logo will be used in many different forms against many different backgrounds and a complicated logo will not transfer as well and while it make look good in some forms it will not in others.
This means that a logo also needs to have horizontal and vertical integrity, meaning that no matter how you look at a logo it should look good either in the top corner of a page, in the middle, or in an app shaped button.
At the same time these rules are merely guidelines. It is not good form to break these rules for no reason, but if there is a good reason to break the rules than do so. I have done several logos in mine line of work and found that simple is better than complex and works in a broader range of mediums.
So as you go to design a logo for yourself or a company, keep these simple guidelines in mind and have fun!