Soil: Moist well drained light soil.  Potting soil with some added perlite.  

Watering:  keep the soil moist in spring and summer, dry but not to the point of shriveled foliage in winter. In dry climates more frequent watering may be necessary.

Some like to mist the leaves frequently, to clean them and  increase humidity… but NOT when the plant is budding or in flower.

Temperature:  give them medium (50 degrees) to warm temperatures during the growing season—spring and summer. The plants go semi-dormant in winter.

Fertilizer: In spring hoyas react favorably to feeding. Fertilize using a liquid balanced food. about every four weeks, three or four times during the growing season will produce a vigorous growth. Withhold food during the winter. More on applying liquid plant foods here. 

Blooms appear in spring and summer when the plant is most active. Lack of water or too much fertilizer will cause foliage to brown around the edges and perhaps leaves will drop.

As with most plants, Hoyas respond to good care. However, they resent pampering, hovering, and constant handling and moving.

One Hoya peculiarity worth noting: They produce blooms on knobby spurs which stay on the plant even after blossoms fade. New buds will be generated there to provide bloom the next time. The lesson to learn: to encourage prolific blooming, leave the flower spurs on the plant.

Also, for fuller flowering, most growers recommend tho keep the roots pot-bound.