You see, on speculative sites like that, where 99% of designers don't have a chance to win, people don't put any thought or effort into their work (including me) because for most of them it's not worth it. Most logos on 99designs are cliche, not print ready, and most of the time plain bad.
On these sites you have to think about players, not designers. Like Poker, the more players there are the less chances of winning you have, therefore you feel less confident, bet small and don't risk. Hardcore players will exploit all the known tricks and cliches to impress clients and win a contest. But what most clients don't understand, from my experience, is that a logo doesn't have to please them, it has to please their target audience.
If you want to build a successful image for your business, find a designer that you can trust and talk to. Go online, look for designer's portfolios, contact them to get a quote and go from there. Also understand that when hiring a freelance designer it's not "work for hire", it's a collaboration, and that's what those sites can't offer, and will never be able to.