I used to have tapes on my violin when I was learning to play, but when you put a finger on the tape you cannot see where exactly it touches the string and likely you are going to be slightly off and even 0.5mm off can be a great difference in the purity of the sound.
The only way to play right is to develop the correct hearing. Listen to a few basic scales and sing them yourself so that you would remember them better. Search the harmony and the beauty in the sounds, that will make the scale more memorable. When playing, do not focus on your tapes, and where exactly you put your finger, put rather be very attentive to what you hear. Can you hear that harmony and beauty when you are playing? Practice playing until you can hear it!
Developing hearing is a gradual process, the more you try to play purely, the better hearing you develop. At the beginning of the practice it takes me several minutes of playing the basic scales to remind myself of the purity of the sound which I could get the last time.
Also developing a good hearing takes a great effort (but in any case it is worthy!). It takes a full concentration, and an empty mind. You are not going to get better just by doing more playing or listening. Maybe up to some basic stage, but not far. Hence make sure that all your mind and body are disposed to play from all your heart before you start playing. Only in that way you can discern every small nuance in a sound.
When I change the note, I approximately place a finger at the correct position, then start moving the bow and as I hear the sound in the first 0.1s I adjust my finger by up to 0.25mm by what I hear. I do all of this automatically. I can imagine for better violinists these distances are even smaller and the time is even smaller as well.
Edit: I just found out that if one plays the violin while hearing other instruments in key such as a piano or a guitar for example, then one can hear the right notes from others and consequently one learns how to produce good notes on the violin too.