Hi! On some days, my voice is amazing! But on others, it just isn't the same. Do you know what that is, and how to fix it?

Many things can affect our voices, including sleep, hydration, hormones, stress, illness, allergies, voice use, etc. The best advice I can give is to keep track of these elements as best as you can and see if any patterns emerge. 

Speaking from personal experience: I have the most consistency when I get good hydration, adequate sleep, vocal rest, and warm up before speaking or singing. 

Best of luck to you!