This helped me to get the lk xx lk.tatsu combo (as well some combo’s on other characters) coming out a lot easier:
Go to training mode, crouch next to the dummy. Hold down (not d/b or d/f to start) and tap cr.lk. As you tap cr.lk spin the stick quarter circle back and tap again. It shouldn’t take you more than three goes to find the timing.
You should be able to do this without tapping lk a second time (negative edge I presume?) - this is how you can tell if you’re doing it right. Just tap and move the stick and you should see the lk xx lk.tatsu comb come out.
Getting timing for moves preceding this is about learning the timing and being able to apply the moves together - in other words grinding out your execution in training mode. Thinking up different scenario’s will (eg empty jump into cr.lp, cr.lk xx lk.tatsu, demon flip/palm cancel into the same, jumping HK and demon flip kick into cr.lk xx lk.tatsu) quickly show you how proficient you are in getting the links right in different situations.