Color Passive skills now. Each color of mana gets it's own set of passive skills you can choose from. Just be careful because you can only have a max of 5 at one time, and for each color you are, you must select at least 1 skill from that color. Each skill also has 3 levels. The levels don't count against your skill count limit but you can only have the highest level of that skill.
One with the land:
Level 1: You may add
to your mana pool on your first turn on your first main phase.
Level 2: You may play an additonal land on your first turn.
Level 3: You may add
to your mana pool and play an additonal land on your first turn on your first main phase.
Beast Call:
Level 1: On your first turn, you may put a 1/1 green saporling creature token into play
Level 2: On your first turn, you may put a 2/2 green wolf creature token into play.
Level 3: On your first turn, you may put a 2/2 green boar creature token with trample into play.
These are just the current examples.
Now to level up a skill, just simply fight in battles. Do note that to get the exp point for a skill, it must be used at least once. For triggered skills, it must be triggered at least once during that fight.