Hello Efteer and welcome back to XIV!

There are usually good grinding spots close to the camp at the right level range (so if you need to find level 20+ mobs, search them close to the level 20 leve camp).

The Moogle Box mob location tool is great for searching monsters and this site has all the most popular EXP camps listed.

People also form EXP parties quite a lot these days (you can see shouts for them in Ul'dah on my server at least). I recommend putting your party search flag up too.

Good luck!