Take it slow
Pick an easy song to attempt first. You may have a dream to play a certain song, but the truth is, if you get too frustrated and overwhelmed, you will give up. Set smaller goals and work your way up.
Same is true with actually practicing the music. Everyone tries to play everything so fast. Sometimes people even get frustrated at how they’re just not getting something, and then suddenly try it super quickly (to compensate) and obviously fail at it. Don’t do that.
Smoothness > Speed
Aim for no stops when you are trying to play something. Even if that means playing the part so slowly that people can barely tell what it is. You are aiming for smoothness, not speed. Once you can accomplish the song/part at that very slow speed without stopping, congrats! You can play that part! Now, just speed it up a little bit, and repeat the process until you get it at the right speed.
Break it down
Isolate the parts or things that you’re not good at. Everyone prefers practicing what they’re already good at instead of what they’re bad at. That’s why people have bad back hands in tennis, or lefty lay-ups in basketball! Find the sections of the song that you always stumble at, and practice those! Sometimes I find myself literally just practicing all the parts that involve my scrawny pinky or my left (hi-hat) foot for whole sessions!
Repetition is key
Repetition builds muscle memory. Eventually you will never need to think about how hard to press down your fingers or how to hold the drum sticks, your muscles will do it all for you. Set goals for how many times you will repeat a section of a song you struggle at, and actually count as you go. I personally use a tally system on a notes app on my smartphone. This will help you feel a sense of a goal, rather than just saying “I’m going to play this over and over.” Aim for: “I’m going to play this measure 25 times, and if I’m not good at it by then, then I’ll have to add more.”
Repetition is also very important long-term. The longer period you spend in between your practice, the more you will start to lose ability and forget how to play what you previously could. Practicing a little often is better than a lot only in one session.
Find a real person to help early
Learning online is awesome and there are so many great resources, but the only downfall to that is that no one is telling you how you’re doing. The earlier you find someone to help you, the better. You want someone who can identify your bad habits early on and tell you how to improve them. Some things people take too long to fix: bad strumming, bad grip on drumsticks, awkward fingerings, etc. Having good form is important because it will set you up to be better when you’re playing harder stuff, so don’t ignore the fundamentals like scales, basic drum patterns, fingering, etc. because they will bite you in the butt later!
There’s no better feeling than finally being able to play something you love. Most important tip: have fun with it!
I hope these nuggets help you to further enjoy this beautiful thing we call music!