This variation asks for a A slow to moderate speed bouncing stroke. bowing and at tempo is best executed by using a brush stroke in the middle of the bow. As the metric pulse is in threes, we need to add an impulse on the beginning of each triplet. Practising spiccato exercises starting up bow is helpful.
The key of Eb minor tests our intonation. Pay attention especially to the Cb on the A string after F naturals on the D string. To make sure that the left hand is always ready to play (for instance in bar 2 with its string crossings) see VLH for Note Ahead practice technique.
If you use Ševčík’s suggested fingering, which is in first position for the whole variation, your string crossing action needs to be precise. Aim for as small a string-crossing action as possible and think about which string-crossing action to use. For instance in bar 2 use a small whole-arm movement to cross to the A string and then pivot back to the D string for the Ab.
Practice this variation to begin with in detache at half tempo to check your string crossing patterns.
Think also when to place one finger on two strings for a perfect 5th. For example in bar 4 place the second finger at the same time on the G and D strings for the fifth of F natural and Bb.
Ševčík adds many variants for this variation and as always these are useful to practice.