I second the two (or even three) piece suggestion. I try to keep the seams at the corners of the fuselage. They are easier to hide that way. Also make sure you work from Bottom to Top when possible, as seams that overlap top over bottom are less noticeable.

Another trick I've used is to use masking tape to tape a straight edge along where I want the final edge. Use three or four layers of masking tape so its raised and easier to see under the covering. Now put the covering on, with the overlap over the tape. After the covering is in place, use a sharp razor to carefully trim along the masking tape edge without cutting the underlying covering. Pull off the masking tape, and you have your final seam line.

Brad