While I have changed my methods because of age, I think you need to:

1. Determine what it is you are after, and the best way to find it.
2. Learn your detector, it's features, , it's audio signals, it's readouts and it's nuances.
3. ONLY search those sites that offer what it is you are looking for.
4. If you are detecting a very old site dig ALL marginal signals (questionable ones).
5. Don't give up on a site that you have researched well just because your first search was not all that profitable.