Help with seaming!

[B]1530 - Plymouth Encore Stockinette Stitch Kimono Pattern[/B]

1530 - Plymouth Encore Stockinette Stitch Kimono Pattern

This is a sweater that I have completed, all but the seaming! I usually knit top down sweaters, which, of course, you do not have any seams! I did get the shoulder seams done, but cannot make myself start the rest! I have done mattress stitch before with some success, but how to do the sleeves? I have looked in the knitting books, but I just get confused. Is there a stitch similar to mattress that you do for the sleeves? I am so afraid of ruining the look of the sweater with messy seaming…I am not good at this seaming thing at all, which is why I usually steer clear of it. Any suggestions would be greatly appreciated, thank you. I did use the Plymouth Encore Worsted to knit this sweater

You would just do mattress stitch for the sleeve seams too. That’s used for about 90% of seaming.