Learning C and Java at the same time.

So i had to postpone my c exam of this semester to the next one so now i have a c exam plus a java exam at the same time. So i have like half a year. Do you have any tips on learning a language especially 2 at the same time? I always hear the only way to learn is to work on something, do you have any ideas for projects or something to learn coding.(would be nice to be a project 2 people could work on but it isn't a must)

Any advice in general is appreciated.