2. Coming unprepared
Most musicians prefer to practice in their bedroom, or a room designated for music or practicing within their home or apartment. Having your practice room close to the rest of the amenities in your living space can sometimes be extremely detrimental to getting the most out of your practice time.
I’m not recommending that you change the space you normally practice in (although this can also be beneficial to getting the most out of your practice time), but by imagining this room as a destination for your practice time, you can trick yourself into staying in the room for a longer period of time.
Solution: One of the easiest ways to do this is by bringing everything you need to the room. Try actually bringing a backpack full of all the things you might need in the next hour, like a water bottle, notebook, capo, tuner, metronome, cables, and something to snack on in case you get hungry.
By limiting the reasons why you might have to leave the room, you’ve eliminated multiple possibilities for distractions, and forcing your mind to focus on what’s important, the room and your instrument in front of you.
3. Practicing parts you already know
A huge tendency for musicians when they practice is to find a phrase, lick, or section that they play really well and play it over and over again, but this defeats the whole reason for practicing! It’s good to be able to recognize when you’ve “nailed” a certain note, scale, or part in a song, but once you’ve realized that you have it down, don’t give in to the desire to keep playing it over and over again.
Solution: If you have a scale that you’re trying to learn, start slow, use a metronome and find a tempo that you can play at comfortably (even if it’s really, really slow). It might seem daunting or even depressing when you try something in the practice room and fail at first, but this is where everyone starts from.
Most of practicing in music is muscle memory, so by starting slow and forcing your body to learn the part at one tempo, you can naturally see yourself begin to nail down the part and speed it back up to its normal tempo. And then you can repeat the cycle: once you have a part down - move on!
Then the next time you practice, you can refresh your muscle memory by playing each part, scale, or song that you practiced and mastered last time in the beginning of the session to keep it present in your head.