If it's your first time, go cheap. I picked up a 20 dollar jacket at goodwill that fit me like a charm. I decided to just "wing it" and it turned out decent, although the inside looks a bit shabby, but who sees that! Anyhow, i basically pinned it like I wanted it, did the sewing, check it again on, then cut off the extra fabric. Then I did the second side.

I have a pic if you go to my profile and check my albums.

I will try to upload close-ups later and show how much fabric I took off.

Best of luck to ya mate! Always remember, measure twice and cut once.