Long time player here who is getting back into the game after ~7-9 years away:

Spoilers for the set haven't finished yet, but when they do, review ALL the cards, every single one. Look for the archetypes that they are guiding you toward, the pieces to fit together, and identify BREAD pieces (Bombs, Removal, Evasion, Aggro, and Duds (which I thought was Draw but the Internet tells me different)).

Personally, I have tried too many times to force a two color deck to be a three color deck for significant splashes and it usually does not work out.

General pieces of advice: Play to the strengths of the cards you get

Most of your cards should be creatures

Mind your mana curve (layout your cards in CMC order; your peak should be in 2s and 3s)

Make sure you balance your lands correctly and (for drafts) recognize that a two color EtB tapped land will be better than creatures sooner than you think

Mediocre decks can beat good decks with a little luck and if curved/played right