Make sure to sell a lot of unid stuff during act 1/2 to get as many transmutes as possible.
I'm definitely not a racer as you can see, but maybe me being slower makes it easier to follow :D
On launch the transition will be a LOT easier due to socket colors/links.
What you need roughly:
2 iron/ruby rings to make 2 ruby rings (iron ring + red gem vendor)
1 lapis amulet (recommended) or spec 30 int node
Level 20 + Alira/Weaver done (19 is also fine)
6+ Transmutes. (If you have very low then make sure to get the mandatory fire res crafts first before buying support gems for scorching ray/rf)
Any Sceptre + shield (can put in offhand during act 1)
Open suffixes on your gear to craft fire res
Recommended: 3 3-Links for Shield charge / Scorching Ray / RF
PoB Including Leveling trees can be found in the guide.
After you reach this point the leveling is very straight forward and no more big swaps happen.
Timestamps:
0:00 Act 1
23:30 Act 2
38:58 RF Transition
46:00 Act 2 Finish
Watch me live on launch be slowge: / nerotoxhs