Etude is a lot like Perpetual Motion in that there's not a moment to rest! Use the same bow strokes throughout and go for a consistent sound across all strings. Notice that this song has many A to D string crossings, and also a few arpeggios and scales inside of it.

G Major scale, Tonalization, Perpetual Motion

Try this to warm up to practice string crossings, begin with a down bow:

ADAAADAAADAAADAA

Try to switch strings with a slight raise of the hand, not a level change with the arm (keep the elbow where it is and use the wrist and forearm to grab the string crossing.)

Try this exercise, break each group of four notes into kernels, work on building speed by practicing each kernel until it can be played fast, for instance in the opening:

1a- (wait, get set, then quickly play) 0d3d0a1a- (wait, get ready, then quickly play) 0d3d0a1a- (wait, get ready, then quickly play) 3a2a1a0a- (wait, get ready, then quickly play) 0d0a1a2a-

until you've made it through the whole song. If you stumble on one kernel, that's the one you need to practice! Practice it this way until you can play the whole piece without stopping. Once you switch back to playing it normally, it should be much easier.

When you're descending the long scales in the piece, prepare your fingers the moment before they are needed. Don't forget low 2s on A & E.

Keep an eye on your left arm elbow, use it to maneuver between string levels if more than a few notes are involved (swing it forwards slightly to grab notes that are on low strings as in the last part of Etude where you're going down the scale to the G string).

Don't use too much bow, play around the middle of the bow, careful not to get yourself too extended at the tip or the frog of the bow, this can cause you to go off balance.