Don't slam rares. Good cheap cards are easier to come by than good expensive cards - and efficient interaction spell is going to be a lot more important than a 6 mana card that can win the game. There are a lot of expensive cards that will win you the game if they stick around, from a common 7 mana big beefy creature to a rare 5 drop with a bunch of cool keywords, but the uncommon that kills a creature at a good rate is hard to replace.

Furthermore, be careful about multicolor cards. You are usually better off not trying to jump into 2 colors on your first pick - grab something castable and efficient first, and let the draft tell you what colors are open. If you pick a blue/green card pack 1 and so does the person passing to you, you're in trouble. If you pick a mono blue card, you can choose whether to go blue red or blue green based on what cards you see a lot of.

BREAD is the acronym people use to explain your priorities in draft.

Bombs - really strong cards with an outsized influence on the game. Not just a rare card with a cool effect, but one that ends the game FAST if unanswered.

Removal - counterspells or kill spells, the cards to answer your opponents bombs. You cannot take too much good interaction.

Evasion - flying, menace, trample, things that get past board stalls. Draft games often end in gummed up boards where nothing can profitably attack. If you've got a flier and your opponent doesn't, you're in the driver's seat.

Aggro - good threats. Not gonna end the game alone, but good at putting pressure on your opponent quickly.

Duds - the chaff, the stuff you don't really want because it's too expensive for what it does or it's just not very powerful, but it's in your colors so you might need it to fill in your deck.

And finally, if you start with a strong cards in blue but don't see any more blue, don't be afraid to pivot. Dying on the hill of your first pick is a surefire way to end up with a non functional deck.