Azorious(WU): Flicker - play creatures with powerful "enter the battlefield" abilities and then recur those abilities by exiling your creatures and returning them to play
Dimir(UB): Tempo Ninjas - attack with unblockable creatures and use "ninjutsu", an ability that lets you swap out an unblocked attacker with a creature in your hand - usually a far more powerful creature
Rakdos(BR): Sacrifice - combine sacrifice outlets with abilities that trigger when a creature dies to double up your value! Play lots of cheap creatures or creatures that can come back from the dead to keep the value going
Gruul(RG): Beatdown - Play big creatures and turn them sideways until your opponent is dead. GG EZ.
Selesnya(GW): +1/+1 Counters - play creatures that care about having counters on them, and then put a bunch of counters on them!
Orzhov(WB): Lifegain/drain - play creatures whose abilities trigger when you gain life, then steal life away from your opponent. Plus, with all that life you'll be gaining, you can spend a few life points for some extra value
Golgari(BG): Graveyard matters - play spells that fill your grave with cards, and then play cards that care about having a full graveyard
Simic(GU): Ramp - Use counter spells to bide time while you ramp up your mana. Then play big spells to close out the game
Izzet(UR): Spells matter - pair lots of prowess triggers, and cards that say "when you cast an instant or sorcery" with lots and lots of instants and sorceries
Boros(RW): Tokens - make an army of tokens that will overwhelm your opponent, and then make that army more powerful by playing cards that buff the whole team
Think of these color pairs as guidelines, not restrictions. There are, for example, many black, green, and blue cards that would fit well in a tokens deck, and it's entirely possible to build a red-white deck that does not focus on tokens. This is true for all 10 color pairs so do not feel like those 10 archetypes are your only options. Each two-color pair also has a secret tertiary support color that can add a lot of value if you can build the mana base to splash it in! Thanks for checking out my cube!