I notice that almost everyone that first starts the game never scouts... and then they are confused when they get cheesed or rushed. I'd recommend sending out a probe or drone at 9 supply, with the probe going after most likely putting down a pylon first. And the scv should usually go scout at 10 after building a supply depot.
You are going to want to do more than just shift click your unit into their base, you want to actually micro it and keep it in there for as long as possible, either until they get zerglings/marines/stalkers to scare your worker away. This will allow you the most information possible.
Yesterday I had a diamond 2s game where I didn't really pay attention when I sent my worker into their base, failing to see that they had in fact rushed me... So going through the motions isn't actually enough you need to be watching your scouter as well.
This is what will happen to you if you don't scout!