Shadowmoor and Eventide are defined by two-color hybrid mana cards that can be cast by two different colors of mana. These hybrid cards are a stark contrast to the typical gold card, which require two specific colors. There are many cards in the format that benefit from staying in one color, whether they count colored permanents or lands of one type. These include staple common creatures, color-defining uncommons, and mana-intensive rares - staying focused is the key to harnessing all of these powerful cards.
The format is designed to support playing one color because hybrid cards can fit into different decks of different colors. In a draft it's possible to focus solely on one color by taking the hybrid cards that include it. The typical strategy in a SSE draft is to stay in one color as long as possible, which not only keeps the deck focused and able to harness color-specific synergies, but flexible enough to splash into a second color down the road.
There are a few key card types that can be found in each color or color combination that are staples for their respective decks.
Cohorts: These creatures get +1/+1 if you have another creature of that color, and they are the premier creatures to fill your curve in all colors except black, which gets a raw deal with the expensive Ashenmoor Cohort.
Duos: Each allied color combination has a Duo creature that receives a unique bonus whenever you cast a spell that shares one of its colors. They're all excellent in decks that share both colors, and most will be staple fillers in any deck that can cast them.
Hybrid enchant creatures: Each allied color combination has a hybrid aura that bestows a bonus to the creature for each color it shares with the enchantment. These are great on creatures with both colors, and sometimes playable on creatures that share one color.
Fists of the Demigod
Helm of the Ghastlord
Runes of the Deus
Shield of the Oversoul
Steel of the Godhead
Initiates: These creatures trigger whenever any player casts a card of their color, and paying one mana provides some small effect. One-mana 1/1 creatures are typically no good in limited, and the same applies here, so don't fall into the trap of playing these without good reason.
Intimidator Initiate provides a powerful effect for the cost, and it's a staple of red decks. Nurturer Initiate is good in an aggressive green deck. Smolder Initiate could be playable in aggressive black decks, especially against other black decks, Apothecary Initiate might be a reasonable sideboard card, and Drowner Initiate should almost always be left out of your deck.
Four-mana */* creatures: Each color has an uncommon four-mana creature with power and toughness equal to the number of permanents you control of that color. These cards provide incentive to stay focused in one color and should be taken as a sign that a color is opened if one is passed to you.
Crowd of Cinders
Horde of Boggarts
Drove of Elves
Lieges: Each allied color combination has a rare Liege that provides a power and toughness buff to each other creature you control of of those colors. They're a great way to start a draft and a strong signal if passed.
Glen Elendra Liege
Eventide adds a ripple to the format by introducing enemy-colored hybrid cards, but it doesn't change any of the format fundamentals.
Mimics: Each enemy-colored combination has a two-mana mimic creature that receives a bonus when you play a spell that shares both colors with the mimic. This means it will only trigger from other Eventide cards, so they play out like Grizzly Bears with occasional upside.
Hybrid enchant creatures: The hybrid aura cycle returns with enemy-colored versions.
Clout of the Dominus
Edge of the Divinity
Gift of the Deity
Scourge of the Nobilis
Favor of the Overbeing
Lieges: The cycle of rare lieges returns in Eventide.
If you have any questions about the format or drafting in general, ask in the comments section. What's your favorite way to draft this format?