(Not) going by the book
I’ve always been one of those people who feels like I need to go through a museum from one end to the other and read all the placards, and the same compulsion seems to carry over to my language learning sometimes. I’ll pick up a textbook and feel like I need to start from the very beginning, even when I know I’ve covered that material before.
It depends on the publisher and the content of course, but don’t be afraid to skip around the book and pick out the chapters or parts that are the most useful for you. Most courses these days seem to structure their material around situational dialogue, and these will mostly be introducing specific vocabulary and grammar points depending on the topic. There’s no correct order to learn a language in (besides the very basics), so while you may need to refer back to look at specific language points, it makes sense to focus on the situations that are relevant, or the ones you’re interested in.
In the same vein, if you have a personal tutor, feel free to mention the situations you feel are most urgent for you to learn, or the topics that you are interested. Most good teachers will be more than happy to include your input in their teaching plans. Just ask!