Practice. A lot. But don't practice by shooting some balls alone. At least not that much. Sure that helps, but what you should be concentrating on is playing other people. People of your skill level or better are perfect opponents.
Remember that each time you make a shot, your brain memorizes the stroke, the "feel" in your arm, the situation on the table (ball positions), the movement and trajectories of the cue ball and the object balls, their behavior, and finally the result of your shot. After you perform hundreds and thousands of different shots, your subconscious mind will start to partly "take over" your game and you'll find yourself hitting better and better with less and less thinking. Making shots will become a simple routine, allowing you to focus on the strategic part of the game.
And that's why it's important to practice by playing matches. If you shoot alone, your brain will only memorize the shots. But when you play others, in order to win, you'll need to pay attention to tactics and strategy. Those will be stored into your permanent memory as well. Your shot may be a little weaker comparing to someone who practiced accuracy for hours regularly, but with little playing. However, after a few months, if you decide to play that person, you'll have all the advantage. He'll be able to aim better, but he won't really know how to use it properly, as he'll lack your experience and tactical prowess. Plus, keep in mind that by playing other players, especially skilled ones, you'll also learn from their successful shots, as well as their mistakes.
My final advice to you is to be competitive. There's no better motivation to improve yourself than when you're trying to win. Still, don't let defeat bring you down. There will be many failed shots, many losses, many missed opportunities, especially in the beginning. Learn something from it and keep going. That's pool life. You'll get used to it
If you have any more questions let me know. Happy shooting
