When I made my first sweater I knew that i could take it to the yarn shop and pay them to seam it. But I thought, why don't i give it a try, or better yet, three tries and see what I can do. I was amazed at how well it turned out. True, I seamed the sleeve to the front edge but it was a neat looking seam before it was ripped out and done correctly.
Give it a go and if the first time doesn't work, try it again until you're happy with it. Jan's idea of seaming swatches is a good one and will let you experiment with different techniques.