I just answered this in another thread so i’ll just copy and paste here.
remember, a lot of us have been doing this for 20+ years. That said, you just need to go to practice mode and stop button mashing. Only hit each button of the combo once. Just let it fail, don’t try and save the combo by mashing. Just fail over and over again without mashing, and eventualy you’ll start to get it. By not button mashing your sub-conscious will start to pick up on the rythm and timing of the game after awhile. Button mashing does not let your get a good feel for this.
Its mental control. Your fingers spaz because you panic. You have to execpt that your gonna fail alot, and just let it happen. Also remember, its better to go slow. Combo’s don’t actualy have to be inputed that quickly, its just a nice relaxed steady rythm.
Start practicing by going slow. real slow. get a feel for the timing on the easier combos. Start slow and slowly build up speed till your at the right point. Trying to go fast right off the bat will cause the spazzing to happen.
Practice does NOT make perfect. Only perfect practice makes perfect. Better to fail 9 out of 10 times hitting only the right buttons, then to succeed a third of the time mashing.
There is no shortcut. But learning not to mash is the only way. Thats your first goal. Don’t worry about getting the combos off now. First get the correct buttons slowly, then slowly increase speed from there.
Also, don’t try and learn the whole combo at once. Just master the first two hits. then add in the third. then when thats perfect, add in the fourth hit, ect ect. Never try and just learn a whole massive complex combo in one chunk.