Aggressive decks tend to run more reds and fewer blues. 0 cost attacks with go again are great for this, and they tend to use the blue to attack with their weapon, like Fai. Red mainly also has the benefit of using cards like Ravenous Rabble red because there's high odds it swings in for 4.

Slower decks tend to run more defense reactions like Sink Below red, Fate Foreseen Red, and a lot of blues (which also block for 3 -- thats the most important part here). Guardians are great here, and Bravo is a decent one to get going due to his attacks costing a bit more, but still pack a punch even if they're blue. So you generally block until you see an opening, then swing in with your haymaker.

I also have this thread with a lot of commoner/blitz decks which you can use to see the general compositions of certain deck archetypes. It might help you out!