KISS KISS stands for keep it simple, stupid. The best logos tend to be simple logos. Handwriting fonts tend to be used for companies that cater to kids, such as daycare or children's software. Script fonts can be viewed as feminine, and sometimes traditional, too. The important point to remember is that the font you choose should convey the image of the company you're designing for.
Color can play an important role in logo design.
The shape of the logo can also effect the company's image. Maybe they're a large company and can afford four color process printing, or have a need for four color advertising. Maybe they're a medium sized business, and can afford two color printing with bleeds and metal plates. You might consider a one color design, with shades of that one color. You'll still need metal plates, but you'll only need one, which will cut costs considerably.