Select all the stuff you want a glow around. Press CTRL+D (to duplicate them). Press CTRL++ (to make them into one path). Now make the path your favourite colour. Press End (to put it below everything) and CTRL+) a few times, until it stands out enough for your liking. Then, CTRL+D and End and make it one shade darker than your previous colour, and press CTRL+) a few more times. Repeat as many times as you want.