Grixis (blue/red/black) is a very difficult build from my beginner's point of view. If I associate a specific word with each of the three colors each word is:
Blue::Control
Red::Damage
Black::Removal
There are seven major types of Grixis decks. Because I pulled two Nicol Bolas, Planeswalker, I am planning to build seven draft decks around these two cards. I am ignoring artifacts for now. That will come later.
1. Grixis Midrange: a balance of blue control, red damage, and black removal. (51-2)/3 comes out to 16.33, and 16 when truncated to an integer. That means we have 16 cards to choose from that each have red, blue, and black. With the RTR block things become a little more complicated because we can choose from black/red (Rakdos), blue/red (Izzet), and blue/black (Dimir) in addition to the three mono-colored selections.
2. Grixis Control emphasizes pure blue. That's 49 blue cards.
3. Grixis Damage emphasizes pure red. That's 49 red cards.
4. Grixis Removal emphasizes pure black. That's 49 black cards.
5. Grixis Emphasis on Rakdos has an equal mixture of red and black. If we only used monocolored cards, that's 24 of each color, giving the splitter card to an artifact.
6. Grixis Emphasis on Izzet has an equal mixture of red and blue.
7. Grixis Emphasis on Dimir has an equal mixture of blue and black.
The next step in this very complex seven deck build is to assign to each deck staples that it must have. These staples form the skeleton of each deck build. Without these cards (and usually a playset), you will be limping along to a loss every time.These staples can either be cards that will help you defend, or cards that will help you attack, and to reassure yourself that you are choosing the correct cards, the major decks you will likely be competing against need to come into the mix at this point.
The next step is to select from the appropriate mana curve for each deck build two or three creatures for each drop (one drop, two drop, three dop, and so on), always keeping in mind what the target for number of creatures should optimally be for each type of deck.
After the creature lineup has been selected, we have 2 slots for Nicol Bolas, Planeswalker, 12 to 24 slots for creatures, and 25 to 37 slots for non-creatures in the main deck and the sideboard.
The question is here then: are we sideboarding creatures? I am not planning to at this point. Maybe with some playtest experience I will change my mind.
Grixis Control is 4 Snapcaster Mage, 4 Geist of Saint Traft, 4 Delver of Secrets with 4 Runechanter's Pike. That to me is the most straighforward of the deck builds because it has such a strong tournament record.
A card that I would like to playtest for Grixis Control is the M13 Jace. I still don't understand the new Jace and will most likely understand it more when someone beats me over the head with it.
And just in case you were not bored with me showing the card these decks are all designed around, here it is. I am a Johnny, allow me to introduce to you my favorite Johnny card in Standard. When it wins, it wins big, but mostly, it sits in your library.