Finding a deaf person who can assist you is what I did….I paid him as helper/tutor….I’m sure you could find someone to befriend as well.
Check/post ads…

Online local sites
local colleges/universities
Local newspapers

Or practice with YouTube videos…...

Try translating news broadcasts into sign language.

Above are all good ideas. I hang out with deaf folks on a regular basis so it is easy to practice and to continue to learn more signs. Here are some other ideas:

See if anyone in your area is hosting a silent weekend. No one talks, it is all in sign.

Go online to youtube (as indicated by @coffeenut) and search for “Deaf Jokes.” This is one example of videos by deaf that you can watch and, because they are jokes, they are kind of fun to figure out. There are other websites with videos where deaf folks sign blogs and I have learned a lot of regional signs and expressions that way.

Become the teacher. Doing this is what helped me retain ASL the best. Do you know any children you can teach?

Everyone above me has excellent answers, I would vote to do all of them. Particularly, the silent weekend!

My input suggestion is to sign while you speak to people. Understandably, you may not be able to do this in all situations, but I recommend doing it whenever you can. Give yourself a morning motivational speech in the mirror – using only sign. Another thing you can do (which is what my friends and I do) is to sign along with songs on the radio. It can be challenging to sign quickly with no pause to think or re-do. I’ve found it to be very successful in keeping your fingers agile and your mind quick. To up the challenge, try occasionally doing SEE instead of ASL. Having to sign out every single word can help you trigger memory.

Hope it helps give you a few more ideas! :)