These days, we're often in loud places where we have to speak over the noise. So if you do that, make sure that you are doing all the same things you'd do if you were singing - breathe deeply, engage the diaphragm, and support your voice. Try to drop the pitch of your voice so that you are using body resonance. Lots of times when we try to speak loudly our voice goes up in pitch, which is a sign of straining.
Be aware! Don't yell if you don't have to! Once you start developing an awareness about how you use your voice, you'll see that you can make better choices. Like walking over to a person to talk to them instead of yelling from across the street! Or stepping outside to carry on a conversation instead of screaming over loud music!
Care for your voice from the get go and you won't have to have the frustration of dealing with a hoarse, scratchy, damaged instrument, especially if you are a singer or speaker. It's all just common sense, but you'd be surprised at how many people abuse their voices, then expect the voice to be healthy and crystal clear. Be kind to your voice - stop yelling!