Too lazy to type this over and over, so I'll copy paste what I posted for someone else a few months ago:
I could give you my entire process but that won't help you much at this stage. Your best bet would be to take intensive classes at your local alliance francaise if you have one. Depending on your country, this could be a bit expensive. The A1 intensive cost me $1200 when I lived in the US. More affordable would be to find a tutor on italki. They'll be one hour lessons and it'll be upto you to put in at least an hour a day outside of classes. Then use an app like tandem for language exchange. It is fairly difficult to find dedicated conversation partners, but you need to start speaking as soon as possible.
Given that you're already 470, you can get away with a low B2 which would give you 12 extra points. A high B2 gets you 62 points, there is no in between. I started from scratch and was ready to pass the exam after 10-12 months. The last 3 of thsoe were just to cross the high B2 barrier. So it is very realistic for you to be able to get to a low B2 in 5ish months. However, I did study for 2-3 hours a day, and used my spare time listening to french podcasts, doing vocabulary flashcards etc. If you want me to get into more depth, I'd be happy to help, but I don't want to hijack this thread.
Edit: There's also a post somewhere of someone, a mother with a young child, who worked fulltime, and passed the exam after 6 months of starting. That post was my inspiration to start learning.
Unfortunately there is no secret sauce. Duolingo is fine as a supplement, but even finishing it from start to finish only gets you to A2. And it's pretty inefficient. And it will not actually help you with the 4 competencies (writing, speaking, reading and listening), especially the first two, which are the most difficult. After I finished my B2 studies, I also enrolled for the Lingoda sprint marathon (look it up on google). It does cost $1000, but you get a 100% refund if you attend all classes for 3 months. This was just so I could cross the low B2 to high B2 barrier. Any specific methods and techniques will only be useful once you're a high B1. Until then, take lessons, and most importantly, start speaking as soon as possible.