Summarize:

Every time you walk into that practice room, have a purpose in mind. And it shouldn't be "to practice violin," either. It needs to be something specific a goal you can work toward. Whether it's fixing a problem spot, polishing a piece, or starting on a new one, have that lined out at the start. And then at the end you'll know if you accomplished it or not. You'll note that with every session, your purpose likely changes. One by one, each little goal will get crossed off, until you're working on more and more skilled issues. This will give you a sense of progress and accomplishment, too, aiding in your motivation to keep going. When we're in the heat of the moment, whether it's violin or otherwise, our brains are so focused on getting the job done that we often don't realize what we're doing wrong. Our foot went too far to the right on the dismount, we sang a note a third too high, or we didn't notice the music in front of us indicated a full rest, and not a half. But if you record yourself, you'll be able to look back and hear where you went wrong, even if you didn't notice it in the first place. If you keep flubbing up on a fast passage, break it down. Play the series of notes, only repeat each note three or four times before moving on (d-d-d-d-e-e-e-e-a-a-a-a), sort of like a bowed tremolo. As you get used to it, you'll have the pattern down and can take out the extra notes. Imagine handing a computer a piece of music and having it play it. Technically, it'd be correct, but it wouldn't be good. Your musicality is your ability to interpret and play the piece with feeling. If your notes are lacking something, this very well could be it. To get started finding this, experiment with different phrasings and variations in tone, style, and intensity. And once it's memorized, you'll be even freer to explore. Once it's ingrained, you'll be able to make it your own.
Determine today's purpose. Record yourself. Think of your musicality.