Learning the basic keyboard shortcuts dramatically increases your editing speed as well as making Photoshop much easier to use.
Remember to select the layer you are working on before taking action on it. If things don't seem to work, then check which layer is selected.
Photoshop settings are sticky, so your last setting remains in every tool until you change it. This can often catch you out when you start a new edit, and is something to always check if Photoshop seem s to be misbehaving.