If you look at double-fold bias tape, you'll see that one side is wider than the other. If you pin the tape around your garment's edge with the narrow side on top and the wider part underneath, you can sew both at the same time. Sewing on the narrower side guarantees you'll 'catch' the underside!
Speaking of bias tape, I decided to use pale lavendar rather than yellow on the dress. I tried yellow that matched the centers of the daisies, and it just looked too 'homemade.' I didn't like pale yellow, either. So I switched to lavendar, and that seems to do the trick.
Do you have any good sewing tips to share? If I can remember to do it, I'd like to start a "Sewing Tip Saturday"--uh, what do you call it? Thread? Carnival?