Everyone makes mistake while typing an email. To correct the problem you need to proof read your mail and correct those silly mistakes while sending an mail. People will always make errors but will not always realize that they have made them. Microsoft Word has its own auto correct feature and now Google Chrome has an extension for Gmail.
The Auto correct feature in this extension comes with a whole bunch of words and the errors we normally make while typing them. Like for example, if you type in the, then the tool automatically changes it to The. So you will not have to right click on words or go back to a paragraph and delete them. The extension will do all that for you.
The extension comes with more than a 1000 words and their errors. You can even add your own word and error so that the next time you type that error, the app will correct it for you.
To add new words to ezAuto Correct, go to Tools -> Extensions and click on options under the installed ezAutoCorrect icon. From here you can configure your auto correct features however you want. On the options page, you can turn on the option to automatically insert a full stop when you leave 2 consecutive spaces.
Check out ezAutoCorrect for GMail.