it's depends on your pourpose. if you want to talk with japanese ppl, the most important thing is pronouncing (i think most of chinese speakers tend to struggle to pronounce sounds "n" (ん) and special accent (sっ).) if you are japanese drama lover, important things is that you used to catch japanese sounds. if you love japanese comics(manga), you need to remember japanese characters (it's not hard for you, cuz some words are totally same chinese characters we use!). good luck~