A good logo should only have one gimmick. A gimmick can be: different colours , changing colours with a simple motif , a single styled letter amongst “plain” letters , a unique typeface used for the whole name , a graphical treatment of the name , or a strong symbol .
Amateur looking logos are often the result of combining more than one gimmick in the one design; just like amateur desktop publishing efforts that try to use every available typeface on the same page. As a general rule, any more than one gimmick will turn a logo into an over-decorated and over-laboured performance. Of course, if the logo were for a circus, this would be a good thing.
When in doubt, keep it simple like: . Simple and straightforward is always better than try-hard.