Foundation is a makeup medium that has multiple ways of effective application. No one way is better than the other, it's all a matter of preference. To choose what's best for you, try one at a time, and see which results look best. Here are some suggestions on how to apply your foundation. Please share your favorite tools in the comment section, there are products out there that we may all need to try! Brushes
The flat foundation brush has been the go to. You can lay foundation onto and into the skin. The first one that I got was the MAC 190. This is just too bulky in my opinion. The Billy B. #2 brush($30) is more user friendly, luxury version.
I'm a fan of domed brushes for buffing foundation into the skin. The MAC 109 brush has been a favorite of mine for years. It works well for light to full coverages. For more sheer coverage, I use a kabuki brush by Sonia Kashuk ($17).
Here's a demo of me using my 109 brush to apply the discontinued MAC Studio Stick Foundation.
I normally run from these because they can soak up your product. Alcone sponges ($3) have been giving me life lately! You can purchase sponges at your local drugstore, but they tend to be much thinner and definitely not at durable.
These are messy, but they are a perfect makeup tool. Your warm fingers melt the foundation into your skin. When my mother taught me to apply foundation, she ran some water over her fingers, put her foundation on her fingers, then spackled it all over. She still has the most radiant makeup application known to man. (Hmm...why am I not doing this? Oh right. I'm lazy.) If you would like a video tutorial on how to do this, feel free to request it. Maybe mommy and I can do it together!