You got the right idea with combos for now and her combo routes are so varied that I'll leave you to research on your own but
-Practice more reverse beats. Eltnum's pressure game is downright one of the scariest since she's got frame-trap tricks for days. Your long range 2/5C buttons lets you engage and disengage into a 2/5A button to continue your pressure
-If not the above, delaying a 22A after a 2C also catches people that are antsy and leads into a full combo
-Weave some 421As and j2B in between said reverse-beat pressure to try and catch people
-Fully charged counter-hit 236A/B leads into a full combo, you just need to run up and 2C for pick-up
-And of course, 214C after anything to confirm for damage, you already seem to have a grasp on this.
Just some basic stuff