Just a little tip i picked up. If you want to grow while producing a settler make workers chop forrest while you build something else. The turn the chop is ready you have to switch fast to settler and then it gets the hammers. Then you just switch back to something else until you have chopped enough to finish the settler. In this way you can continue to grow while "building" a settler.
Update: Leov found an easy and hazzle free way of doing this called the cancel-chop method.
Basically you look for when the worker has two turns left to chop a forrest. Then you select chop so that he has done his move for the turn - THEN - you cancle his orders. Next turn you can chop the forrest finished when you need it. This way you dont have the stress of fast switching etc that can fail sometimes. If you need a more detailed information on this method you can read leov's post here
Update: Leov found an easy and hazzle free way of doing this called the cancel-chop method.
Basically you look for when the worker has two turns left to chop a forrest. Then you select chop so that he has done his move for the turn - THEN - you cancle his orders. Next turn you can chop the forrest finished when you need it. This way you dont have the stress of fast switching etc that can fail sometimes. If you need a more detailed information on this method you can read leov's post here