1 - The Better Way to rack pickets
Many climbers don't give a great deal of thought how to rack pickets, usually just slinging them over their neck. Well, this is just about guaranteed to dangle, tangle, and strangle, and if you're doing a long running belay with more than about three, it gets even worse. This applies to the leader as well as the cleaner.
A much better method is to clip a carabiner through the third hole of the picket, and carry the pickets vertically clipped to your harness. Here’s a separate post that describes how to do it, with some pictures.
2 - Consider a whistle
Running belays require clear communication between the entire climb team, to tell the leader to stop and place more pro, or for the team to stop while the last person cleans.
If it’s windy, the route goes around a corner, you have your hood cinched down tight, you’re wearing a windproof fleece hat, your ice tools are knocking off chunks of ice and snow, you’re mentally focused on a tough lead . . . or all of the above, it can be very hard to hear the calls for “pro” or “cleaning”. Consider whistle blasts to signal the leader to stop and place more gear. Wear the whistle on a short cord girth hitched to your pack strap and be sure you can get to it with gloves on and using one hand.
The leader doesn’t need to have this, but all of the following climbers should consider it.
3 - Running belays - Max party size is three
A simple rule of thumb for running belays is this - keep the party size to 2 or 3 people max on a rope. With more than 3 people, it’s almost always faster to fix the rope and have the everyone come up on a fixed line or simulclimb.
Reason: if the team always keeps one piece of pro between team members, with four people on the rope, the leader has to carry and place a LOT of gear!