Robots.txt can be a easy way to improve your traffic and make google engines more firendly for your website. Here is a nice and simple post that explain what we can setup in robots.txt file. You can setup files and places that you want to show and limited access to admin parts of your Wordpress files.

If you want you can check my file here.

You can see also example in post that i wrote about. It takes only 5 minutes to deal with it.