1. Any day is a good day to shoot. Don't put your camera away when it's overcast or rainy. Those cloudy skies act like a giant softbox and can be great times to shoot, especially since full sun can result in colors that appear less saturated. And those rainy days are great too. The wetness and clouds can create a dramatic mood in your images. Raindrops can also create great reflections and add interest.
2. On sunny days, shoot with the sun to your back. Shooting into the sun will create haze, lower saturation and can result in dark shadows and a loss of detail.
3. Adjust your white balance. Check your settings and try different things to see what you get. You may like the result of a warmer image if you try increasing your kelvin number slightly or using the cloudy setting. Some DSLR's have mode settings for landscapes or vibrant subjects. On my Nikon there is a setting for "vivid." Check your manual if you are unsure how to change this.
4. Try underexposing just a bit. You'll up your saturation that way, watch your shadows though.
5. Look for contrasting colors to make them pop. Golden leaves against a blue sky are gorgeous! Play with different color combinations by moving around to get different angles and compositions.
6. Go wide and get close. Sometimes you want a wide sweeping shot to take in a whole forest of trees, but getting close with tiny details on leaves, bark, acorns, etc. can showcase beautiful colors and patterns as well.
7. Keep an eye out for reflections. That gorgeous tapestry of leaves will reflect beautifully in calm waters. Lakes, rivers, even puddles work.
These are just a few simple tips to get you started.
What's your favorite way to capture the colors of fall?