This is a beginner's first attempt at a control deck with a Planeswalker,
Control deck using black and blue spells with a couple of win conditions. Uses Ashiok, Nightmare Weaver as one win condition and Colossal Whale because why not. Standard blue counter cards are used and black spells attempt to reduce opponents cards.
FYI, this deck is not meant to be the best. It's made of cards that I had in my collection, not the ideal cards.
Blue instants and sorcery spells should be used fairly early to prevent opponent from gaining ground early. As always with control decks, try to keep enough mana open after your turn to be able to use your instant spells (keep mana open even if you don't have an instant in an attempt to keep your opponent in the dark). Once enough mana is open for a Diabolic Tutor (4 for Tutor and ~3 for an emergency counter spell), grab one of the win cons, preferably Ashiok if it is still early in the game since that will be a bit more reliable than the Colossal Whale.
With the Planeswalker out, use the +2 every turn, until a useful creature is exiled, or if the counter reaches >10, start thinking about exiling the opponents hand. Before doing this right away, use a method to peek at their hand (Duress, Lifebane Zombie from sideboard). Another move would be to use Disperse on opponents cards before using the -10 to instead exile that card.