Learning to play an instrument is like learning to speak a new language. You may be able to say a few words, enough to greet someone and order food in a restaurant. As the years go by you pick up more words and with experience you can talk with others more fluently. If you want to get good quickly, you need to surrounded yourself with the new language. This is how I like to think of learning music. You will pick up new phrases to add to your musical vocabulary by spending time with an instrument and by listening to music, reading books about music and by having someone teach you. With regular guidance and practice you can speed up the process of learning, especially if you study theory. If you can make playing an instrument as much a part of your life as speaking, you will get good quickly. Jimi Hendrix carried his guitar around with him wherever he went!