If you want to learn how to play guitar you need to practice. Books and teachers can show you how, but your fingers have to learn. You’ll need to develop muscle memory. The parts of your brain that control the motions of your fingers allowing you to play music need a fair amount of drilling before they’ll cooperate with what your mind tells them to do. Practicing allows you to embody the knowledge you get from teachers and books.
Some people do best with regular practice schedules like an hour before dinner every day or an hour in the morning before going to work and an hour at night before bed. If you really want to be good you need to practice about five hours a day, maybe more.
If you are a disciplined person and you like regular schedules, it’s pretty easy to block off certain times in the week when you practice without fail. Some people don’t work that way. For some having a guitar within easy reach and objectives in mind is the best way to do the repetitions necessary. If there’s something you really want to be able to play, having a guitar nearby that you can pick up and bang through it just one more time is very effective. Then there are binge practicers who will have something they really want to be able to play and they’ll work and work until they get it down.
I’ve practiced all three ways. Once when I was studying with somebody very demanding, I took a calendar and a stop watch and decided to practice 1000 hours, so when I was actually practicing the stopwatch was ticking away and I wrote the totals for each day on a calendar. Somewhere in the mid-600 hours life intervened and I abandoned the project, but the amount of time I put into it put me into a different league as a guitarist.
I’ve also set aside a couple hours a day to just work on a particular instrument and found that very effective. I’ve had guitars scattered around my home all within arms reach, and I would just pick them up and play them frequently and found that helped quite a bit. When I was 19-20 years old I typically had a guitar in my hands for 14 hours a day and my friends started calling me Guitar Tom.
Leading that sort of guitar obsessed lifestyle makes the guitar very familiar in the hands. I would suggest that you find the best way for yourself, the way that best suits your personality and lifestyle at the time. But remember, the more often you pick up the guitar and the more that you hold that guitar the better. As far as music is concerned, either you can play it or you can’t.