The Importance of Light for Nature Photography
The word photography literally means "to paint with light," and it is the creative use of light that can make the difference between snap shots and beautiful photos. If you want your photos to have that extra quality of warm sunlight to bring out detail, you need to be photographing when the sun is low in the sky.
As the sun comes up and is low on the horizon, the light it creates covers the earth with a warm glow that brings out detail and casts wonderful long shadows. Conversely, it also happens when the sun is setting at the end of the day. The down side of this that for photographers it means no sleeping-in on workdays. Get up early and you will not only have the chance to be outside during one of the best times of the day, but you will also improve your photography. This works well for those who like a good road trip, since it enables you to photograph first thing in the morning.
Once the light has gone, you can get some driving done to be at your next photo site in time for nice afternoon light. Don't get me wrong, if you happen to be someplace really fantastic at noon, and the photo of a lifetime presents itself to you, take it; but if you have the chance and the time to be at the right place for the best light, that is when you should be photographing. This can be challenging when you are traveling, since you may not have control of being at a location at the right time of day. A festival's parade may not start until mid-day, or you may only have a few hours at the location before you need to move on, or it may be raining the day you are there. In these cases you simply make the best of what you have.
Don't be afraid to use light to enhance your photography in creative ways. Many will tell you that it is best to have the sun at your back, i.e. you between the sun and your subject, but remember that side lighting and backlighting can be very useful in photography. Sidelight can create wonderful shadows while backlighting can give your subjects a nice rim light to make your subject stand out. Unfortunately, wildlife is not always in the best place to be photographed. A subject might be backlit or standing in shadows, or you may simply have to make the best use of what light there is. Try not to judge this as a setback, but rather a challenge and chance to be creative. With that said, you should realize that sometimes bad light is just bad light, and it may be better to try to maneuver to a more pleasing angle, or just enjoy the moment without getting it on film.
I would add that inclement weather can be used to make beautiful photographs. Use the atmosphere to make images more interesting. Fog, rain, and snow it have been used to enhance photography. When you are out in nature, if you are not prepared and comfortable you will not want to take the time to photograph correctly. The lure of hot chocolate (or a hot rum toddy) inside may make you miss some wonderful opportunities.