A lot of good comments so far. About the only thing I'd add is that you might want to intentionally double-charge a case just so you know what it looks like and have a visual reference for comparison. Just be certain to immediately dump the powder from that case when you're done comparing so you don't inadvertently seat a bullet on it!
I'd also recommend a different powder for standard pressure .38 loads. For +P loads, Power Pistol would probably do well (I haven't tried it, but my favorite midrange .357 load uses PP), but for standard pressure you'll probably be happier with a slightly faster burning powder like 231, or even faster still (Bullseye, Clays, etc.)