Youtube is your friend. If you can't figure out how to do something, search for it on google and you might come across a video. Usually I do this for basic stuff, like cutting a hole in something. It's very easy to use software, but it also depends on your computer skills. Especially when it comes to modeling, doesn't hurt to have some CAD experience.
I just wish I could find models for bulkheads, etc.
There are also many user contributed sketchup templates available for download, which may help you get up to speed.
Do a Internet search on - sketchup templates, select the one that has 3D Wharehouse in the title. You can then search within the site for the template you want. (Aquarium, Sump, PVC pipe, Bulkhead, Etc.)Where would I find these goodies?
They have a few sketchup bulkhead models on 3D warehouse.