Master control of the cue ball.
Practice safeties by getting the cue ball to rest, frozen or near frozen to a ball and/or rail.
Str8 Pool is another game that has a lot of safety play.
1P is a wonderful game. It's hard to find people to play it, but some old farts play it exclusively. Find one of those guys and play'em. Even if it costs you a little money, it is usually worth it. Most of the time, they'll play for free because there's no one to play with, and will help show you tips about the game. I was lucky to play a guy at Shoreline Billiards. He showed me a lot, and when I got good at it. I noticed he started playing some really awesome shots. I watched and learned.
I sure would like to find someone in Austin to play some 1P. I refuse to play 1P, solo. Like in the game of Str8 pool, it is better for you to have an opponent. Otherwise, you just knock balls around. By having an opponent, you will play better because if you leave an open shot, it will cost you...big time.