I do the same thing I always press everything so I have "locking" seams. once you start doing it, it kinda just comes natural and you don't even have to think about which way to press so your seams will all butt up to each other. I don't use alot of pins when I am quilting however when it comes to matching seams I always stick a pin in right at the intersection. A dot of glue and a tap from the iron is great for holding these seams together also. This way you know your seams are not going to budge while your sewing.