The animation is done very smoothly for the overall level of detail, as for the explosions...
To be honest, from what I've seen in most successful cartoons/Anime, is that they simply draw the explosions with little to no special effects added, this can be a difficult learning curve.
Essentially just watch a bunch of movie clips of ACTUAL pyrotechnics, and knowing you, just give it enough time and things such as explosions, clouds, dust, and fire, will become second nature.
Best of luck!