I’ve never bothered with any of it.
I drop the kids to school. Stand around with them for about 2 minutes before the bell goes, then head back to the car. No time for chatting.
Rinse repeat at home time. Arrive, wait a minute or two, collect and go.
I see the same groups of Mums chatting in the same old spot every day, and the same parents standing on their own every day, it’s an even mix.
They’re only cliques if you desire inclusion. If you want to use this 2 minute opportunity twice a day to make new friends, it requires steadfast effort to break in, show enthusiasm, bring something to the party, ...
and then begin a 5 year commitment to all the joys of passive aggressive why didn’t she nod hello or talk to me this morning or laugh at her joke but not mine or wave goodbye or invite me for coffee after drop off....
I did try once and made what I thought was a fab new friend, she was new to the village, all hippy trippy arty farty, our kids were similar ages, and as she garnered new friends around her, we we’re invited to a pub, and they all sat there nodding and agreeing with Miss I Love Animals And Everyone’s Beautiful that the village council estate residents were scum (her words) and let the place down, and I balked inside realising rainbow triber was a phoney, and before you know it, bam, school gate tensions, Queen Bee rises, .... luckily I’m a loner by nature so slipped away unnoticed. I wouldn’t choose to make a school gate chum again.
Anyway, cliques always have a leader just remember, and they probably use bully tactics to keep their minions loyal, however mild or obvious. I’d recommend making friends with the parent who always stands alone, not the bunch of Mums who always stand together.