For any garden, you need to look at the amount of sun that it gets and make sure you don't over crowd the space. If the balcony rails let air and light through great, if it is a solid wall, sometimes that can be challenging since plants don't do well next to a solid wall.
The amount of light you receive will determine the type of plants you grow. You will also have to work out things like how you are going to water without leaking onto the level below or somebody's head. Small plants can be watered in a sink or bathtub. Larger plants can go into self watering containers or if you use saucers, you need to be careful not to let the plants sit in water. If it is windy, you need to find plants that can tolerate it and pots that won't fall over.
Happy gardening in Hawaii. Gardens are where people grow.