I am entirely self taught, I’ve been playing for three years, and the only thing I have trouble with is timing, I have trouble keeping a steady beat and I play very sloppily when it comes to timing.
I’ve tried a metronome, I still have a problem trying eighth and sixteenth notes at slower tempos
Getting a metronome is great answer but I have another trick I think will come in handy. Find a recording of a song that you know you are having trouble with timing on. Now record yourself playing along with the song, trying to match the recorded guitar part exactly. When you play back your recording you should be easily able to hear where you got off in timing. Rerecord and repeat. It’s a frustrating and time comsuming method but in the end I think you’ll find it works.
Now if you really want a unusal method of getting timing here it is: take dance lessons. Learning to move your entire body to music will translate into developing natural timing.