Mulligans
General Mulligans
You want to ramp early to have the mana edge on your opponent. Seedsman can draw Dew Process. Azshara is also nice to have early to activate the effect. Dew process is the core card, activate it when you have solar eclipse or when your opponent has a filled hand. Aquatic Form is always a keep.
Aggro Mulligans
Aggro ist the hardest matchup for this deck. Don't keep Dew process because your opponent will likely be able to play many cards every turn so you just help him by giving him extra draw. Instead go for removal and lifesteal so he will eventually run out of cards. Sheep+Fanboy+Hedge Maze can become a Reno-like heal on a full board.
Survive with lifesteal and removal and mill your opponent with lots of draw. Works best against control decks.