Okay, well.. Ninjutsu is actually the core ability to manipulate your chakra, as well. Such as being able to walk on water, run up trees, etc. etc. From the basic manipulation of chakra, we learn to give them a nature, such as fire - Which you're learning atm as well, if I'm not mistaken. Anyway, considering you've probably already advanced through several jutsus on those lists, we won't pratice too much on the basic stuff.
However, try walk across the water surface, exerting a layer of chakra at the bottom of your soles. Keep it balance, so you won't fall through.