If your hair is lacking moisture, then there are two steps to be taken: determine your porosity and update your routine. Your porosity will help you determine what kind of moisturizer will work best for your hair. I have low porosity hair, so I use a lightweight moisturizer that absorbs into my medium textured strands easily. If you have high porosity or normal porosity hair, you might need an additional sealant. The LOC method may be worth a try. The method is simple. You use a water-based leave-in followed by an oil and a cream styler. Also, if you're not using a deep conditioner regularly, you should start. Having regular conditioning incorporated into your regimen is key to moisture balance.
If frizz is a problem, then you might try smoothing each curl with leave-in coated hands. Avoid handling your hair too much after you apply your styling product(s). Some curlies have better results with styling soaking wet hair versus damp hair.