Here is a quick tip that I use all the time when I am typing on my iPad's on-screen keyboard. When you need to insert a quotation mark, the official way to do it is to tap the key that with the label .?123 and then tap the key with the quotation mark on it. But that is two motions — first tapping the key in the corner of the left side of the screen, and then tapping the key with the quotation mark near the right side. There is a faster way to do it that only involves one simple swipe.
To do this, press down on the key that has a question mark at the top and a period at the bottom, and then quickly move your finger up a little bit. You will see a quotation mark appear in a pop-up window, and just slide up a tiny bit to turn that quotation mark blue to indicate that you have selected it, and then let go. Bingo: instant quotation mark with a single swipe, and without having to press one key on one side of the keyboard and another key on another side of the keyboard.
If you want a single quote mark instead of a double quote mark, you can also use one swipe to do that. The only difference is that you swipe up from the key just to the left, the one with the exclamation mark and the comma. Tap down, quickly swipe up, let go, and then say hello to your newly inserted punctuation mark.
Those are the only two iPad keys that let you use that quick swipe up gesture, but keep in mind that you can hold down on many other keys for about a second and then swipe up to access additional characters. For example, hold down the E key to get the letter E with different accents on it, useful for typing in foreign languages.
One hidden mark useful for lawyers: the section mark. To access it, tap the .?123 key, then hold down the ampersand key. After a second you will see a § floating in a window just above the & key, and you can swipe up to select that section mark.