Your logo is a big part of your business brand, in fact it can be the foundation of it. It should be bold, memorable and versatile enough to work across a variety of mediums, not just on your website and in print. If you have a van or a shop or unit front to apply it to it needs to scale up, if your employees wear branded clothing it would be useful if your logo works in block colour.
Think about any successful logo and you could probably easily draw it on a piece of paper with a few quick strokes because simple things are easy to remember. Also, complex logos, or a logo that relies on texture, gradients or lots of colours won't be as versatile as one that uses simple, distinct shapes and easy to read fonts.
There are trends when it comes to logos, but your logo design should be classic and timeless, or it could date your brand very quickly.