A good curved dildo is like a sledgehammer to the smaller toy's tack hammers
. It's hard to miss with a dildo.
You can usually find your prostate easier when you're very excited, especially when you're near orgasm. It gets much firmer, and you'll feel it as a pronounced bump in the front of the rectum (towards the penis). Fingers should be plenty long, otherwise it would have been noted in medical literature.