A freshly-transformed Vampire is relatively weak, with plenty of weaknesses and few abilities.
However, there is a ritual that can increase your power:


First, you will need a "Blood-Soaked Coin", made in a crafting table with a Gold Ingot in the center,
two Bat Wings to the left and right of it, and a filled Blood Bottle below.









Once you have your Blood-Soaked Coin, you will have to throw it into lava.
Doing so transforms it into a Blackened Coin, which you'll have to collect.

By using this item, you can unlock new abilities such as turning into a bat.