The following techniques are in no particular order. I will list them as they come to me, hopefully starting with some basic ones and moving on to more difficult/time consuming ones as I go.
Possibly one of the easiest ways to really add that little extra to your layout, inking can be your best friend. I know people who ink EVERYTHING, and their pages just have a flair to them. It makes a huge difference, whether you ink a lot, or just add the minimum edge to your papers. Here is an example of a page that is not inked, then inked, so you can see the difference.