ALWAYS use a line

Bring a hamper full of "pre-infs" for the most labor-intensive parts of the most complicated choices. (Mine is full of princess-dresses, Ariel-tails, braided unicorn-horns, Nosetongues for dogs, ears for dogs, mice for the cats, horse-bridles, Minniemouse-bows, etc.)

If it's a girl's party, have NO LESS than 6 unicorns already twisted up to completion---face & all. You also may want one of each princess: Ariel, Elsa, Rapunzel (sans hair), Cinderella, Belle, Snowhite, and Aurora, all done & ready. Just for safety, go ahead & have 2 flower-tops standing by as well. All these will either save you time in the line, OR enable you to make FAST replacements if one pops after making.

If it's a boy's party, have maybe 4 bows already made & strung, along with at least 12 arrows. And probably 2-4 of each: Hulk, Spider-man, Iron-man, Lightning McQueen, and if there are below-6's---have at least 2 Thomas-the-tank-engines.

Okay, that's how to go in loaded for bear & keep the line moving fast. Now as to keeping the child at the front AND all the others in line entertained the whole while:
The sleep-routine. Have a 'blanket' made of material you can see through, and every now & then after finishing a balloon, sit in the chair, yawn, say "NIGHTY NIGHTY!" and put the blanket over your head, making loud snoring noises. It wont take but 2-10 seconds for a kid to yell to wake you up, at which point you holler, throw off the blanket & fall to the floor. Gales of laughter ensue, and it gets funnier everytime. (dont overdo it though!)

The gunshot. Have a small, tightly twisted balloon on the floor near your foot. When a kid asks for a gun, make it, then subtly position your foot on the small balloon. Tell the kid "Oh, don't worry, it's just a balloon! This gun will NEVER---" And at that momment, POP the small balloon!

The wrong sound. Do you have a sound system & an ipod / somesuch? Have various animal sound loaded, and after making an animal, say "Watch how real it sounds!" Then hit the most ridiculously wrong animal sound possible.

The bagpipes. If a kid asks for a guitar, or ANY musical instrument, blow up a 32" round, and 4 / 5 260's, twist the 260's together any which way, stick them & the round balloon under your arm, put one of the 260 tails into your mouth, and hit "Scotland the Brave" on the Ipod. When the kid repeats that they wanted a guitar, look at the "bagpipes" and say "Well, ALMOST!"

What great suggestions. Thank you for sharing

Blow up a 260, snap it in the middle, your face registers "oops", and let the halves go - they will fly off with a screeching sound.

Make it fun and entertaining, be funny, BE FUNNY, use slapstick and verbal humor, be interactive, chat with the kids, ask them questions, get names, mix in quick magic, don't be a balloon twisting robot like most people. Of course you have to balance the length of the line with how much other stuff you do so the line doesn't slow down too much, but if you have a long line and you aren't adding comedy and interaction, etc then they will get boored. If you can't be funny and entertaining and interactive while doing balloons, maybe you shouldn't do balloons.

The balloons are an extension of the magic show—the fun continues with a balloon show. I make an announcement that Im going to make some animals—and the kids have to guess what animal I’m going to make—before I make it. I then proceed to make 30 different single balloon sculptures intermixed comedy and slap stick humor while the kids are yelling out their guesses or imitating an animal sound in order to win the balloon. It’s fun for the kids ame me.

????? see my Dec.28,2020 post - above - "POP" -tears galore - no more .