I have never really ran a fast 1500m yet, but my plan is to sort of start roughly the same as my 500m, then slow down and get into a bit of a rhythm that's very painful but not impossible to keep up and then just keep going for what feels like at least 55 minutes until I'm at 1500m. It's too short of a distance to be able to afford any kind of getting into a somewhat comfortable rhythm, but too long to just go full retard. I guess there's a reason they call it the hardest one
Today in the 3k I thought I started out pretty strongly, but if my last kilometer was almost half a minute faster than my first, there probably was a bit more to win there. But, as I'm sure you know, there's that fear (well, more like a factual knowledge) of it going to hurt like an absolute bitch and not starting too fast (or fast enough) feels like a way to ease that.
Last Saturday's 500m had no pacing. It absolutely hurts like all hell and you feel like you've just inhaled the core of the sun into your lungs, but at least it's straightforward: go out sprinting as fast as you can and don't stop moving until 500m is done even if your legs are really, really, really struggling to simply keep your body upright in the last 150m.