Long lines only happen during peak times, holidays etc. Most of the time Universal isn't that crowded so front of line is helpful only on packed days.
Animal Show, show up 15 minutes before. Rarely a line.
Water World, 15 minutes before, as long as you're in the que you will get a seat. All seats are good but if you want front center then 20-30 minutes prior. An crowded days they usually add a show right at park closing thats announced late in the day.
Terminator, bad lines only on busy days.
Shrek, most in que line will get into next preshow.
Tram Tour, can get bad line mid-day on moderate to busy days. Otherwise averages 10-20 minutes wait.
Simpsons, bad line almost all day every day unless very uncrowded day. Often they don't have all cars operating for some reason and line crawls.
Jurassic Park, bad line only on very busy days in which case can be 40-60 minutes. Otherwise 5-10 minutes.
Backdraft, Special Effects, typically 15-20 minute lines on most days unless very crowded.
Mummy, 15-20 minutes on low to moderate days, 30-40 on busy days.
My typical plan is to get to Universal at opening. Ride Simpsons first thing. Next head to the lower lot and do all rides and shows there. Lines will be short here as most people do everything on upper lot first. Next, take tram tour if busy day, otherwise see Water World, Shrek and Terminator first. Animal Planet can be seen when convenient.