You want to train your finger strengths, a classic way to do so is squeezing a stress-ball, or just a regular tennis ball. By doing so you'll get stronger fingers, something that's useful even beside playing guitar.
If you're strong enough, you can do pushups on your fingertips.
Also, take some times to REALLY listen to music. Listen to how it's built. This will make it easier for you to do a cover, or even compose your own music.
Remember that it takes a lot of training and effort. I wish you the best!