There is an option within your Gmail settings that will allow any new contacts to be saved, in order for their email address to be auto completed the next time you start typing their name.
It may not sound like much, but you will actually save so much time with this feature enabled, that you’ll wonder how you got by without it before 🙂
To make sure you have this feature, go to the cog in the top right corner, and select Settings…
Make sure the General tab is selected and scroll down to the Create contacts for auto complete section…
Tick the line that says the address will automatically be saved to contacts and that’s it!
Very quick and easy, and I wouldn’t be without it 🙂