This whimsical, elegant variation in triplets develops Ševčík’s interest in beginning a bow stroke on the string and then finishing that bow stroke with up-bow spiccato or another off-string stroke.
As with the other variations, practice the basic stroke on open strings paying attention to your bow speed and bow division. For the first three notes work on making a focussed sound while leaving enough bow to play the up-bow spiccato notes with a sense of ease. In bar 1 and similar places work on having one continuous smooth right arm movement independent of whether playing slurs or up bow spiccato.
Make sure when you add the left hand that shifting and finger fall is even and reliable so that the bow can move without hesitation. For instance, place the 2nd finger as a fifth on the first beat of bar 9 so that the bow can make a smooth string-cross.
In bar 23 check that the 3rd finger calmly navigates moving between a ‘high’ position D# on the A string and the ‘middle’ position A natural on the E string. Practice the pattern on one string to focus on the two positions of the 3rd finger.
Pay attention to the phrasing off at the end of each musical line especially in bars 12 and 24.