It's so hard to explain to someone in words how to drive a manual. Honestly, it's just a 'feel' for what the clutch is doing. Some manual cars are easier to drive than others too as you begin to drive different cars that have a manual transmission. You just need to practice, practice, practice, and after a while you don't event think about it anymore.
Here's a good video that explains how a clutch works, that may help you understand what you are doing while you are driving.
So basically, when you are 'slipping' the clutch you have not fully released the pressure plate to engage the clutch disc against the flywheel, which will eventually wear down the material on your clutch disc if you 'slip' your clutch all the time (watch the video(s) for everything in this paragraph to make sense )