We've got just over 1,000 cache finds under our belts and some days we log DNF's until my fingers are just plain tired of typing!! After reading the other replies, we agree with what has been suggested. We would add a few other points tho.
1. Be prepared to touch ANYTHING not nailed down (even some things that are). We have cache containers that were made in our garage wood and metal shop. Just because it looks like it belongs there, touch it anyway! Twist it, turn it, look under it for string that holds the container down in a hole, look inside it (but be prepared for bees) but be careful not to break anything.
2. Go to events and ask that question! Local events might just get you to meeting those cache owners and you can ask for a hint (doesn't mean you'll get one or even a good one but you can ask ). You will also get a sense of the kind of person the owner is and where they might hide things. Hints from other members of the group about the toughest hides in the area are also possible.
3. As a cache owner of some pretty difficult hides, we have to grit our teeth when someone with under 10 finds tells me my 4 difficulty is missing. Not that it might be, not that they couldn't find it but that it's missing! For example, we have a 1/1 in our backyard. We were watching the cachers from our window and they couldn't find it after 30 seconds. They walked off before we could get out there to help and posted that it was missing. They had 2 finds!! We wouldn't have minded if they'd said "Hint please?" or just "Nada on the find" but missing..aargh!! It's better to just state "Didn't find it after so many minutes of looking" or just ask for hints. Always check the difficulty level. You might find a 4 or 5 and DNF on a 1 or 2 but it's always nice to know the number.
4. Don't give up and don't take the hobby too seriously. There are so many reasons to cache. You will enjoy the hobby a lot more if you figure out what your reason is! We cache because the hobby takes us to parks, lakes, historical areas and railroad overpasses that we would NEVER have found on our own. Getting exercise looking under light pole skirts doesn't hurt either!
Good luck and keep caching!!