Step 1 - Don't go to internet forums to get advice on nutrition and how to lose weight. You'll just get confusing and contradicting opinions, and quite frankly some crazy suggestions.
Step 2 - Do some research on reputable sites, and find some good books to read on the subject.

When I was out of shape and just beginning I reminded myself "You didn't get in this bad shape overnight, you're not gonna get in good shape overnight either."