I find that textbooks can be really good, and CGP guides are also usually good.
When you look through the textbook, put a post-it note next to anything you don't understand, and email your teacher about it (or post on here, we are always happy to help!).
BBC Bitesize is quite a good online resource, and there will be lots of youtube videos on different topics.
In terms of questions when you aren't sure, try and figure out what topic it is linking to. You might have to think about the links between bonding and boiling points for example.