My timing is pretty bad. Help?

[David Jayne]

It is very difficult to play in time if you don't master what you play. It is as simple as that.

QFT.

 

[Dbassmon]

Yes to most everything said in this thread and a couple of additions;
Metronome√
Practice Slowly and Accurately until perfect before speeding up√ (practice does not make perfect, perfect practice makes perfect)
Click on 2 and 4 - will help you make things swing, good time feel√
Record yourself - cruel but very informative√
Learn to visualize the pendulum of the metronome in your mind's eye... not sure if anyone else does this, it works for me√
Pay attention to where most player screw up the time feel... drag the groove and rush the fills - be conscious of this is only way to address it√

 

[mambo4]

Definitely Metronome first.
Another thing that helps timing, unmentioned so far,
is learning to read/write rhythmic notation accurately,
at the very least down to the 16th note level.

at a certain point you should know with certainty where every note you play falls in the bar.
or at the very least be able to quickly identify it.
It completely eliminates any guess work.