A lot of it is just practice and figuring out how you work best. Some ideas:
I try to make up all of my icings at the beginning of the week so that all of that is ready to go when I'm decorating. It saves a lot of time, and keeps your momentum going, when you don't have to stop and mix up icing while you're decorating.
In fact, do as much ahead of time that you can. Try to get any gumpaste pieces done early if you can, get all of your boards ready, etc.
Your soccer ball looks fantastic!
i do a bunch of cakes every saturday, agreed about making the icing ahead.....i ice all the cakes friday afternoon so all i have to do is decorate saturday....makes all the difference in the world.....have all the tips organised.....star tips together...rose tips etc.
i line the iced cakes up on bakery racks according to time due with their order tucked between the doilie and cake pad....just go down the line.
for awhile instead of using 100 parchment triangles i just loaded basic colors in the canvas bags, and just switched tips all day...(dang i forgot this, i need to start this again.
after you are in there awhile, you'll be amazed how many you can do.
instead of the buttercream transfer, i'll cut out a little stencil material pattern the day before....you can use this as a negative stencil...like say for the horse...instead of freehanding if you cut a stencil ....lay it on the cake...airbrush whatever the background will be...then lift the stencil off....then just fill in the white shape that was left...perfect every time!...i LOVE stencils!
and i've started using chocolate molds alot this year...so much faster than drawing stuff...and cheap!...you can color the white chocolate any color ya want...you can get a lot of molds for under 2 bucks....i bet i've used the guitar mold and the castle mold 30 times already...i have a cowboy boot and hat thats really popular too.
Just like costumceczarina says, I make all figures the week before. Earlier week of, I do all frostings and fillings. Bake Wednesday, frost and frill Thursday, decorate Friday, they are bye bye on Saturday. 5 cakes though? Wow. I can't do that many. 3 cakes, tops. maybe when my 3 babies under 3 get older, I'll bump up the number.
Hats off to you! five cakes is quite an undertaking, and you soccer cake is so cute!