This is the real trick to any language learning. I tell my students, you have to keep exercising the muscle. You have to want it. If you don't you will not do well and you will waste your time. Think of the gym. People can go and just sit on the machine. Or they can go walking and complain that they don't have bigger muscles.

We have to attack each area like its a muscle group. You have to have a routine and stick to it.

One way I do this is by adding a little project feel to the process. What do you really want to do? What is your end goal? Who are the people you will be communicating with? There are many guidelines for good project-based learning for free online at pblworks.org but people shy away becuse it seems too "big" of a goal. Really, you can do workbook exercises all day but if it's not interesting or applies to reality, you are not going to be able to stick with it.

What students can start doing is look at real webistes in the language. Use google translate to explore words they don't know yet. You are going to find that words like virus and technology are going to be the same for a lot of languages. You can decipher sounds and spellings from that. Go back in yout workbook or whatever exercises on grammar and use those words. Expand! Explore! Take a walk, and come back.