3 Problems Help please!

I have 3 problems with my wordpress site, it’s my first WP Template.

1. I have a space between my header and my content, i had read some topics about it, but can’t find the answer.

2. I want to use faux columns but they don’t work, see my site:
http://wiljanslofstra.crispypoop.com/wordpress

3. I want to center my whole site but it also don’t work can anyone explain me how to do this.?

I hope anyone can give me some answers!

– Wiljan Slofstra
(Sorry for bad english)