Good tips there. Some additions:

One of the most common mistakes in frontline (especially in seize and shatter) is putting your team in a flanking situation.

This is due to ignorance, laziness, tunnelvision, etc.

In my experience this happens a lot. One usual situation in Shatter is that your team chases other team back to spawn after big crystal, ignoring position of third team, resulting in a flank at the bottleneck close to the team you are chasing.

How to avoid:
Always keep in mind where opposing teams may be. Never chase other team if you don't know position of 3rd team (if you know, it may be ok if you can steamroll other team for free points).
Stay focused to avoid tunnelvision.

And, this is a general rule. Stay together. This is true in almost any situation. There are exceptions, like when all tiny ice spawns at once in Shatter. And you don't need an entire alliance to reclaim base from 1 nin. But if you're not sure, stay together.

Be careful going to big ice furthest from spawn.
For example, if you spawn east, be careful going to big ice south-west.
Your team can't escape easily.
Your team gets flanked much easier.
Better alternatives could be taking enemy bases. this seams to be the meta at the Japanese datacenters.