10ths are just octaves plus a 3rd so all the patterns that we know for 3rds apply to 10ths. Start by playing broken 3rds, firstly 3-1 up the A-string, then 4-2 up the E-string.
By shifting on a higher finger (the 3rd or 4th) you are more likely to shift both fingers together.
Then play broken 10ths, again making sure that both fingers stay on the string and you are aware of whether the shift is by a whole-step or a half-step.
Like all double stops you can also practise 10ths in mixed rhythms.
SEE
Practice - Mixed Rhythms & Bowings
Scores - 10ths - Broken Chord - violin & viola
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