"Practice makes perfect" is an internationally-known three-word sentence that is probably used most by music instrument teachers. Nowadays it has perhaps lost some of its status but it's still very much out there, ringing in students ears.
I guess the more reasonable quote would be "practice improves", as "perfect" is something that is luckily impossible to achieve in music. In order for practice to be an improving action, it should be done in a way that not only focuses on the details of music/ technique but also keeps a watchful eye on the physical state of the player.
Without a doubt, the violin is one of the most physically demanding instruments to play. The unnatural position required to merely hold the instrument can automatically create tension. On top of that, the set of activities that are required to actually play the music (reading, sound production, awareness, rhythm etc.) make huge mental and physical demands on the player and need equally careful attention from the teacher. This is just as true in the beginning and middle stages of learning the instrument as in the more advanced.
Therefore it is extremely important to ensure that when playing, the required movements are emanating from a relaxed body and not a tense one. Asking questions such as; "are my shoulders relaxed?", "are my knees free?" or "am I breathing normally?" can all help pinpoint unhealthy habits that you perhaps didn't know existed: the kind of habits that could probably cause playing-related injuries in the future.
Addressing these aspects as early as possible with the help of your teacher is highly desirable, as the longer we let the tension exist, the harder it is to eradicate it.