Ha ha. Our favorite? Stagger! People think that you should all group together like a traditional portrait. But nope, fill in the foreground, center and background.
I have short arms too so I tend to hand the phone to someone with the longer arm. That person should be in the front. Everyone else should stagger into the frame from there. Hold it up higher to fill more of the frame…plus gravity pulls down so your neck and cheekbones are better accentuated. tee hee! More flattering for us women. ha ha
Worse case, use a selfie stick or phone tripod. I’ll throw it on a gorilla pod because that gives just enough length to make it work. Use the 3 second timer so you don’t have to press the button yourself. https://amzn.to/2DbkMrb
I prefer the gorillapod because it’s smaller, flexible and easier to take into places like Disneyland. Selfie sticks are banned there.