Don't waste your money on a lawyer. Like it's already been said, GC application is pretty straightforward. After you've completed it, make sure that you triple checked it though. If you have any questions, just ask here.
Also, one key piece of information. For documents with your signature, DON'T send photocopies. Send the original. I know of 3 people whose GC process got delayed due to submission of photocopied documents ( with their signature ).