Tea tree oil is an excellent disinfectant. It is effective against bacteria, viruses and molds. In fact, a hospital in California did a study where they used tea tree oil to clean with for a month, and it was just as effective as their normal bleach-based cleaner. If you only want to disinfect, just water and TTO will do it. Vinegar is good for cutting soap scum on mirrors/showers. It is also a fairly good disinfectant on its own. Other essential oils have cleaning and disinfecting properties, and some I use just to keep things smelling fresh and pleasant.
One thing to keep in mind when switching to a natural cleaner - Windex and othercommercial window cleaners contain wax. When you first switch to a natural cleaner, you might see streaking on your windows/mirrors. This does not mean your homemade cleaner is not working - it is just trying to clear the wax buildup. Try adding a couple drops of castille soap (Dr. Bronner's is a very common, easy to find brand) to your window cleaner just until the buildup is cleared.
Microfiber cloths are also very effective for cleaning without even using chemical cleaners. I use microfiber cloths and plain water to clean my mirrors, and it works great. Follow the washing directions carefully for microfiber, and wash them by themselves to maintain their effectiveness. The ones in the auto section of WalMart or Target are much cheaper than the ones in the cleaning section, and they are exactly the same thing. If you have a Sam's Club membership, theirs are the cheapest - about $11 for 25 large ones versus $2-4 apiece for the ones in the cleaning section of most stores!
On final thought, both baking soda and vinegar are good for cleaning; however, remember that baking soda is a base and vinegar is an acid. Cleaning recipes that combine the two will not be as effective, since they neutralize each other. Keep researching online; there are a ton of great recipes available. If you want to contact me directly, I think I have some stored in my computer that I would be happy to send you.
Best of luck,