Yes use this too! Also don't forget holding shift when on the pen tool can work as a straight edge to make your straight lines if you're too lazy to switch around.
There are also build in perspective rulers for backgrounds, although I personally have not used those because I'm too used to just doing things the old fashioned way.
Another suggestion for lineart (although not software specific)is doing longer, quicker and more confident strokes- this usually produces smoother lines.