Everyone will have their own ffordd, but for what it’s worth, this is what I have done.
I did old course 1 followed by Levels 1, 2 and 3, then I did the vocab units of old course 1 and then I did old course 2. I’m currently working on vocab units of old course 2 with a plan to then do old course 3. After that, I might go back and quickly revise a few things and then, perhaps move to the North Wales courses (although I have done the South Course, I’ve noticed that BBC Cymru, books, videos, etc often have bits of “north” and bits of “south” through out so it might be good to be aware of the differences.
A super important part of it all, however, (if you’re not doing it already) is practice with real welsh speakers. Where I live the easiest way I can do that is through welshspeakingpractice.slack.com, which has many people from this forum meet regularly to practice. It was a bit daunting at first but the very kind and friendly bunch there helped me gain in confidence and my listening comprehension is improving dramatically. If you have people around you to speak to, that’s great. Otherwise, come and join us on Slack! (more info on this thread: Finding practice partners - a new resource - please share). The good thing is that there are 1:1 chats as well as group chats.
Other things I’m trying to do is to read “real” content such as BBC Cymru, which has a vocab function from the website (ie not on iphone app, etc) that helps you to define words you may not know. Also, I have recently bought a book that was recommended here “e-ffrindiau”, which is a book made for learners. I’m also trying to listen to and watch “real” content (although that is a bit tricky in terms of variety in Australia!), usually online.
Well, that’s my 2 cents.