Lighting: Hoya Macrophylla does best in bright light, and a little bit of direct sun is just fine. In fact, some direct sun is beneficial in helping the Hoya flower. However, make sure to protect it from scorching hot summer sun! Indoors, a south or west-facing window is ideal. Variegated Hoyas need more light, but solid green varieties tolerate much more moderate light. A solid green Hoya Macrophylla will be a-okay in an east-facing window. Outdoors, Hoyas will love bright shade, especially if they hang under a shady tree and get dappled sunlight.
Watering: During growing season - when it's hot and humid and sunny - water freely. In the winter, reduce your watering and make sure the soil dries out almost completely. Hoya Macrophylla stores water in their fleshy, succulent-like leaves, so if you forget a watering or two, your Hoya will forgive you! A good rule of thumb is to water when the leaves start to pucker just a little bit. However, letting the soil stay too dry for too long (like one might let a cactus dry out) can damage the Hoya.
Humidity + temperature: Hoya Macrophylla THRIVES in humidity. Other conditions like lighting and water can be less than ideal if the Hoya has high humidity that mimics their natural habitat. For this reason, Hoyas make wonderful bathroom plants if you have the right lighting! I have some of my Hoyas in more moderate humidity (around 40%) and they do fine, but I've seen a dramatic increase in growth once more humidity in introduced. Additionally, if you decide to mist your Hoya Macrophylla, don't do so when the plant is flowering.