Jeliness2 wrote:Ehm, I played Op.25/6 and now they come out fine. But, you don't have to do that i guess.
Though I assume your thirds had to be pretty good before playing this etude.
When I want to bring out the top note in intervals, btw, i usually practice just the upper note without the other one (with same fingering as you would use otherwise, but keeping the other finger as still as possible. After a while, that melody / finger pattern becomes memorised, so then, even when playing intervals, the upper note finger is stronger.
At least that is how it works for me, but it is very difficult to give general advice on these things of course.