After using an iPhone for a couple of months now, I think I've finally figured out how to type quickly on the iPhone with the fewest number of errors. There are two keys to effective quick typing on the iPhone:

1 - Make sure you don't miss any letters.

2 - Ignore your errors as you make them.

These may sound a little odd, but let me explain and I think these simple rules will make a bit more sense. The iPhone has excellent auto-correction but it is based on the number of letters entered in a word and it is also based on how close the "wrong" letters are to some expected letters. For example, if you are trying to type "football" but instead you type "fooball", the iPhone will not be able to auto-correct this. But if you enter "foorball", the iPhone will recognize that the "r" is right next to the "t" and when there is a "t" in this word it makes a lot more sense, so it will correct this for you. But for this to work, you need to keep typing after you type the "r" so that it can see the entire word and figure out the correct replacement. Yeah, when you enter the "r" you can stop, backspace and delete the "r" and put in a "t". But if you had kept typing, the auto-correction would have saved you. In the end, to get good typing speed on the iPhone, you need to let the auto correct do the work for you so you need to ignore the mistakes as you make them.

If you do this, and you make sure you enter the correct number of letters for the word, you'll find that your typing speed on the iPhone will improve significantly.