See the picture:
This picture shows the pop-ups you'll get when you hold down the iPad's "E" or the "N" or the comma or the period (dark gray keys). The blue shows which symbol will be inserted if you let go without doing anything more. It's easy to get an accented "e" in this manner-- just hold the "E" key, slide up and over to the accented "e", and then let go.
There are many other keys (including the vowels) that will also pop up alternate symbols if you press and hold, so experiment a little and see what you can find. The numbers keyboard also has some alternate symbols-- give that a try as well.
Using this press, hold, and slide method you can save yourself a trip to the numbers keyboard just to get an apostrophe. Now you know how to get an apostrophe from the ABC keyboard, by pressing and holding on the command key. It's only a second or two, but they add up.
Try it. You'l like it.
BONUS: when addressing an email you get a different keyboard. On that one, holding the period down gives you .com, .net, .org, .edu, and .us (in addition to the period). How handy is that! It's my new favorite shortcut. Here's a picture.
DOUBLE BONUS: a lot of this works on the iPhone as well.
