To determine the total cost of a spell, start with the mana cost or alternative cost (such as a flashback cost) you're paying, add any cost increases, then apply any cost reductions
Glorious Sunrise is an enchantment that gives green decks a ton of great options
Combine her with a Vorinclex Voice of Hunger and a Doubling Season, and you could be taking opponents of the game super-fast
Fetchlands like Misty Rainforest are great ways to reset the top of your library to get a fresh look with The Fourth Doctor, but Id also recommend trying out cards like Bant Panorama and Shire Terrace which enter the battlefield untapped and tap for colorless mana in the early-game, and then you can cash in for a basic land and shuffle your library later when you need it
This creature reads: Whenever an opponent casts a spell with mana value 3 or less, Scalding Viper deals 1 damage to that player. Basically, if youre against a deck that purposefully keeps their cards cheap, a single copy of this card could end them
If an effect allows you to cast a spell with certain characteristics, consider only the characteristics of the door you're casting