You might think you will never get this - but you'll be surprised at how quickly it can become almost second nature.Getting the rhythm outside of the piece was crucial to me. Debussy's Arabesque was one of my first 3 on 2 as well. What worked for me was tapping my left hand on my left knee for the two and my right hand on my right knee for the three (and/or the other way around). Start out with just one hand and then add the other by first just doing it on the first beat - so one hand plays three while the other hand plays one. Then once you get that down, make the other hand go twice as fast - the second beat coming just after the second beat of the triplet hand.For faster speed - the usual rules apply. Get your single hand fingerings down and play the separate hands at speed.Also do a search over this site - this question has been asked a lot!
I use the Phrase " not hard to get" to count 3 against 2 lol.
Here is a trick that one of my teachers learned from Eugene Liszt.
Here is a trick that one of my teachers learned from Eugene Liszt. It works for any and all poly-rhythms, as well as most difficult black key passages.First, you transpose the rhythm to C major. In the case of the Arabesque, you play from C to F in the right hand, and you play from C to E in the left hand.You start at the same time in both hands, and you focus on ending together. It doesn't matter if you play fast or slow as long as you start and end together.Then, you continue to play the right hand in C major, but you now play the left hand as it is in the score, e.g. measure #39. Then, you do the reverse by playing the left hand in C major, and the right hand as it is in the score.Finally, you put the two together as they appear in the score.The same technique holds true earlier in measures #19-21, when you are playing two against three with two in the right hand.There is also the old "1 ta li 2" method with the second note of the duplet being "li" and "1 ta" being the first two notes of the triplet. I find this to be better suited to Brahm's Intermezzi where he uses it a lot in order to create a special harmonic rhythmic tension, which is not the case in the Debussy.