Keep training your previous material, just as hard. New material is to be added to the old, not in replacement of the old.
One of the biggest mistakes people make is to stop training the earlier material when they get new material. The things you are being taught are parts of a working system. The more of it you know and understand, the more of the complete system you have. But all parts are important, even the older stuff. The newer stuff gives you an opportunity to claim a larger portion of the complete system, but the older stuff gave you the base on which to build with the new.
This becomes obvious when you test for your next belt. I am always amazed when people get freaked out over the fact that they are getting ready to test, and they just found out that they will be tested on ALL the material that they have learned, not just the new stuff for the current ranking. But to me, this never should be in question. It should be obvious that you need to keep training it all.