Sketching a simple part, trying to break out of AutoCAD mindset

I drew a very simple part that is to be storage shelving for my garage. I am new to SW, converting from AutoCAD. I sketched the wood to dimension, extruded, and constructed the main "body" of the part. I would like to add drill holes where needed (which I started to do) I was doing a sketch for each set of holes. I'm assuming there is a quicker, or more effecient way to do this. Should I have sketched the holes at the same time I sketched the wood parts? I am still getting used to the different mind set of SW compared to AutoCAD. Thank you in advance for any assistance.SolidworksSketching