Full sun to partial shade. Most Crassula plants need some shade in the hottest part of summer, but require bright light to attain their most vibrant color. A site with morning sun and afternoon shade would be perfect.
As succulents, they don't need frequent watering, since they store it in their leaves. If they are left to sit in wet soil, their roots will rot. During cooler months, give them a good drenching and then allow the soil to dry out, before watering again. Crassula plants go dormant when the temperature gets hot in summer and need even less water.
Feed sparingly. You can give your plants a little organic fertilizer in mid-spring, as they start actively growing.