Once you get the hang of playing around with your Intro Deck, you will begin to notice that some cards are not performing as well as you hoped. Your Intro Deck should also include a separate booster pack with 15 new cards. Look through those and see if any in your colors could increase the power of your deck.
The more you play around and the more cards you have access to, the more powerful you will be able to make your deck. As you start making changes, there are a few things you will want to remember about constructing your deck:
• For most duels you will play, 6o cards is the minimum size of your deck. This is the rule for all “constructed” formats where you start with a deck pre-built.
• Of those 6o, you will want about one-thirds to two-fifths to produce mana in order for you to consistently play your spells. Look to play 22-25 lands.
• Try to stay as close to 6o cards as possible, it will increase the consistency of your deck. • Constructed decks have a “four of rule. This means that you may only have four copies of any card of a given name in your deck. but this does not apply to basic land cards.
• In addition to the 6o cards of your main deck, you may also have a sideboard of additional cards to help make your deck better against certain weaknesses. The sideboard must be exactly 15 cards.
• Try to vary the costs of your spells. More expensive spells will be more powerful, but you will need things to cast in the early game as well or you might not survive to cast your slower, more powerful spells.
• Competitive Magic duels are played in a best of three series. Make your main deck as powerful as possible against a random opponent and use your sideboard to tweak specific weaknesses against decks you have trouble with.