You need to tribute to summon? Use your opponents board instead!
The best cards to have in your hand on your first turn are Unexpected Die and Rikka Petal. With those two cards you can potentially full combo both the Rikka and Sunavalon cards. After that Unexpected Dai will likely be a brick since you can't be controlling monsters to use it.
Also when using Sunavalon Dryas, first you should special summon Sunseed Twins with Sunvine Sowing, and make sure you never put it in the zone right under your Dryas. This blocks the Dryas effect as you cannot special summon another Sunvine link from your Extra Deck since the zone Dryas is pointing to is blocked.