Before jumping in. Do tonnes of research. I say this as someone who didn't and regretted it massively.
Here's a few more tips:
Whatever you do - get everything in writing.
Follow up on every "verbal" conversation with a text/email confirming any changes you discuss.
Even a "just to confirm, we'll be adding x extra" or "just to confirm, we're no longer needing that y". Sounds silly but will save you massively in the long run if ever anything goes tits up.
Don't pay cash in hand. I repeat. DO NOT PAY CASH IN HAND.
Don't pay weekly either. Have a clear payment schedule that involves payment in stages (after bits of work are done).
Get a contract in place.
Get recommendations from people who you know. If you find a builder you like, ask them for the details of someone who they've done similar work for. If they're legit, they should be able to give you this. Don't fall for good reviews online - ask to see ex-work!!
You can never have too many plug sockets in a room. Ok, maybe you can lol but better to have one or two extra than what you think you need.
If the house hasn't been fully rewired in decades, better to do a full rewire now, rather than a partial and again in a few years.
Don't get sucked in by fancy lighting shops you see online. Amazon and Wayfair can be your best friends.
Paint looks different depending on lighting etc. It might look nice on Insta but you'll probably need to double check with testers in your own house.
Renos run to time, so expect an extra month or so to be tacked on along the way.
If your walls start cracking like crazy after they've been plastered and attempts to patch them up aren't working, your job's botched and will likely need redoing. Some small cracks are normal. But huge cracks? Nah mate. To be doubly sure, knock on the wall - sounds hollow? It's blown.
Ok I'll stop now! Hope that was helpful. Was wildly cathartic for me after the shitstorm my reno's been lol. Feel free to message if you have any more Qs or want any clarification and good luck xxx