i got to 460 before doing any raids, mostly got lucky with heroic darkshore and the heroic loot you got from the 5 mythic weekly cache, and doing 3 chest visions
At 445 I 1000000000000000000000000000000000% suggest you start looking at your best pieces stat wise rather than just looking at ilvl
Do M+ in range 5-7 (8-9 are only more difficult but weekly chest is the same that 7).
Once you’re near 460 try grouping for +10 and beyond.
Do visions, once your cloak is R15 you can 5 chest for 470 gear at 450+ ilvl.
Do Mythic+ 8-10's, do Normal/Heroic Ny'alotha, spam rated Arenas and BG's, or something like that.
Or, you can follow the gear guide people have already shown and re-posted earlier in the thread.
Fact (because I say so): TBC > Cata > Legion > ShaLa > MoP > DF > BfA > WoD = WotLK
My pet collection --> http://www.warcraftpets.com/collection/FuxieDK/
download fake achievement, open /LFR, join HC group.
Or better: Look for a nice guilde, do Heroic one evening a week.
Fact (because I say so): TBC > Cata > Legion > ShaLa > MoP > DF > BfA > WoD = WotLK
My pet collection --> http://www.warcraftpets.com/collection/FuxieDK/