Use a plain unsweetened yogurt. This can be used both internally and externally. Make sure that it is sugar free as yeast thrives on sugar. You can use both store bought or homemade yogurt.
Garlic is a great natural treatment for yeast infections because it is a natural enemy of yeast. All you need to do is insert a garlic clove or capsule every few hours as needed to alleviate your symptoms.

You can use apple cider vinegar to help alleviate symptoms temporarily but I noticed that it doesn't always work as a permanent cure. The best way to use apple cider vinegar is to add about a cup to a bathwater.
One of the best tips that I have come across is to drink plenty of water. I have found that when I am properly hydrated I am at a much lower risk of yeast infections. It is recommended that everyone drink 8 glasses of water but some women need more. Like I said this and many other great ideas are in Kill Your Yeast Infection, so you should definitely check it out.