I put a black ribbon on a bottom of a square cake I didnt get the nice edges I wanted how would I get the nice square effect on the cornners

Are you talking about square icing corners or square ribbon corners?

If it's the icing that's giving you the problem, here's some photos on how I do it. I do a lot of square cakes ... I actually prefer them to round ones.

http://www.cakecentral.com/cake-decorating-ftopicp-5396443-.html#5396443

If it's not the icing you're referring to, let us know and we'll pop back in to see how we can help.