First time building PC

I was just gonna buy the most expensive parts first to get it out of the way but now I'm hoping to get feedback on what the smart thing to buy first is. I was thinking to buy the high priced stuff first to get it out of the way and maybe cause prices will fluctuate idk.

And also since its my first time building a pc any tips on what I should be wary of or something when I build it and just tips in general will be helpful and appreciated.