Watch videos of professional matches. Especially watch pros who have great pattern play and/or a rhythm at the table that you particularly like.
Recently I didn't play for about a week (which is typical for me) but made sure to watch a few minutes here and there of Efren's matches on Youtube (which is atypical for me). When I next played, my stroke was rusty but my pattern play was better than usual. So much of this game is mental that you can keep yourself mentally in stroke even if you are not physically in stroke.
Edit: In order, I would say the best things you can do are:
1) Watch videos of professional matches. The more you watch great players, the more you start to internalize their decision making, their mechanics, and their level of focus. This will stay with you when you get to the table.
2) Learn. Watch instructional videos, read instructional books, etc. There's a limit to what you can learn without being able to try it yourself, however.
3) Practice your stroke. Unless you're a beginner or are working on a very specific mechanical issue, I think practicing your stroke at home without a pool table is only marginally helpful. You're not lining up on a real shot, you're not actually striking a cue ball, and you don't have any real world feedback to tell you what you did right or wrong. It's so different from playing that I don't think it's that helpful.