Keyframe Substeps

It is often the case that high velocities will need high sub-steps, well will benefit from high sub-steps especially if using particles. Take an explosion for example where you are blasting out hundreds if not thousand of particles for maybe only 2 or 3 frames which die off after a few frames. I would generally set my sub-steps high but that of course wlil really slow the simulation down. However I often get away with 10 or 12 sub-steps and increase the simulation timing to say 3 or 4 hundred percent. Then slow the timing down to say 80 %. In this case 12 sub-steps is overkill and I key the sub-steps down to 1 by frame 20. You of course can play with the fcurve for this.
You will see that as you sim the SS in the container read as fractional but in the Sim window the SS are showing as whole integers.
It really does make a big difference to sim this way.
OK obvious I know but for beginners may be a useful tip.
Key frame as much as you can to get the look you want. Emitter distance. size, expansion etc etc.
Density thickness is always a good one to have keyed as is the fire white balance and damping.