Delicious colors, great job. SITD is a good idea for a first quilt. As for thread, I'd suggest you do a sample with different colors of thread on the different fabrics, that way you'd know if you really did or did not like the result before you were committed to the whole thing. For long lines of straight stitching, I found that blue tape on top is a great marker and helps keep the fabric straight too. I use the same tape a couple of times before it doesn't stick too well. Have fun, glad you've joined the gang!