You are training muscles to remember patterns of use.
Each position has a three dimensional setting of the arm, and hand on the fingerboard, like a GPS reading. The distance between each set hand position can be measured by the thumb and fingers sliding up and down. The ears should both predict coming notes and judge their correctness.
The first fingered note to remember is A on the G string. As Andrew McG suggests, turn out the lights and shut your eyes too. Reach for A, correct it, study the setting of your arm, drop your hand by your side then reach for the same place. Test and adjust. Keep repeating the process and quickly discover that your muscles have a memory. Repeat for D, this time with the pinkie. Try scratching the back of your head then reaching for D, or scratching your right shoulder or touching the top of your scroll. Reach for D thinking "tuning position." Then try shifting from A to D and back, thinking Position to Position, distance moved and note to note.
There are ways to quickly find notes, even in orchestra, however very quiet harmonics can still carry a long way!! The note A sounded on the G string and tested against open D will locate Half and 1st positions and find notes from G to B. The G harmonic over C can locate notes from B flat to D. The D harmonic over D can find C to E. The thumb planted in the curve at the bottom of the neck will locate IV and V Positions very securely. F sharp is an octave+a third above open D and makes a sweet chord and Octave G is a Harmonic that is not quite directly over the same note fingered.
There are three sizes of shift, Small, Medium (or Walking), and Bungey (or Death-defying Leap of Faith). Small is a 1/2 or whole tone distance moved by the hand, eg G A B C played 0 1 2 4 on G string. Medium is when the hand walks up and down the neck from note to note in say groups of two notes, eg G A Bflat C D E F on the G string. In both cases you can measure the distance travelled by the thumb and fingers sliding up and down neck and strings. In the largest shifts such as jumping to B flat in Thumb Position from B flat on A string the thumb and fingers must often let go of the neck completely, hence the Leap of Faith. Usual advice here is think only of the pitch of the note that you will land on and trust your muscle memory to do the rest. This actually works!!!!
The gradual process of learning all your scales, Major and minor, over at least over two octaves with Major minor Dominant and Diminished arpeggios, will end up polishing and honing both your note finding and shifting skills.
Hang in there!!
DP
