Thoughts on the format
As has been pointed out before, there aren't too many terrible cards in this format. You are spoiled for choice, and will usually be able to build a few different decks.
There's more mana fixing in this format than there are multicolored cards. Even an aggro deck should never have any problem playing three colors.
There's a lot of removal, so you won't have to value it too highly, but a lot of it is situational or expensive, so decide what kind is best for your deck.
The format feels faster than it looks. Boros "go wide" has plenty of support between tokens and pumps, and Temur has a nice balance between cost and size. Even the Abzan mechanic 'Outlast' is good in aggro decks, since they can build up their guys whenever they're not able to get through, while the control deck usually can't afford to take them off blocking duty for a turn. However, they only need one counter to start acting like Slivers, so be aware.
There's a bunch of lifelink, but lifelinkers can't block evaders, so a lot of the time it works just as well in an attacking deck than a defensive one. I predict that if the midrange deck is able to turn the game around after surviving an aggro onslaught, the aggro deck is not necessarily gonna have a million turns to draw into some reach, so anything that helps you race is good.
In all my games, whoever got to be the beatdown won, but that's not a good representative of the format since I built my deck to be good at beating down and terrible at being beaten down.
Morph is the most interesting mechanic in the format. Many times, I was paranoid that my opponent had a
Watcher of the Roost to suddenly block someone they shouldn't have been able to, though it never happened. Most of the morphs that are cheap to flip up don't gain extra toughness though, so if you want to trick your opponent into wasting a removal spell on a morph that won't die then you'll need to keep a bit of mana open.