Notice the different types of lines on your paper. Each row has a thick line on the top and the bottom, and a dotted line in the middle. Different letters have different heights - some will reach from the bottom line to the top, and some will be only between the bottom and middle lines.
Write out the alphabet in capital letters. All uppercase letters are "tall" - that is, they reach all the way up to the top line of each row. Some letters, like A,B, E, H, and K, have lines or angles about halfway down, and you can use the middle line as a guide.
Write out the alphabet again, this time in lowercase letters. You should notice most lowercase letters are "short," reaching only to the dotted line in the middle or each row. The only exceptions are b, d, f, h, k, l and t, which are just as tall as uppercase letters.