The day before a fast it is important to keep your body hydrated, well nourished and away from caffeine and alcohol.
I hate to beat a dead horse, but it is just that important to get lots of water the entire day before the fast, not just the last hour. You should also eat throughout the day well balanced meals and snacks. I suggest starting with 1-2 eggs, a slice of whole grain toast and a banana. Then try a small yogurt with a few nuts or granola for a mid morning snack. For lunch have a vegetable and pasta salad with a scoop of tuna or cottage cheese. Throw in a fruit and some nuts or hummus if you like before getting ready for the main pre fast meal.
Before Tisha B'Av the last meal will actually be the Seudah Hamafseket, read more about that here, but before that you should fill your tummy with a solid meal just like this one:
This salmon recipe can be your entire meal, it is filling and nutritious and perfect before a fast when combined with rice and lentils too.
You could stop with the salmon dish, but we are heading into a fast, so a little asparagus with lemon and walnuts steps it up a notch.
End your meal with a little something sweet made from dates. Dates are high in potassium which is good for you before a fast. If you don't like Date Balls, try Date Pinwheels, Dates with Almond Paste, or Raw Date Brownies.
Wishing you an easy fast.