I'm fascinated by the Battle of Hastings, and something that has always interested was the appearance ( uniforms, colors, armor, etc.) of people of different factions throughout history. Recently I've been trying to see differences and consistencies in artwork depicted battles like the one described, and seemingly Normans and Anglo Saxons are depicted exactly the same on the battlefield. Was there any one thing or collection of things to signify which banner you were loyal to? If so, was it obvious to everyone or was it difficult in battle to tell who was who?
How can I tell the difference between my Norman comrades and my enemies
At risk of sounding facetious, they're the ones at the top of the hill behind the shields, while you and your comrades are the ones at the bottom. To be real though, early medieval conflict appears to have been a relatively regimented affair centred around massed infantry formations with peripheral skirmishing, rather than the chaotic wheeling melee usually pictured in popular culture. We know from depictions in the Anglo-Saxon Chronicle, Asser's Vita Ælfredi and poems like The Battle of Maldon of battles such as Ashdown, Brunanburh and Maldon that not only was the shield wall formation central to English warfare, but that it was also used by contemporaries. At Ashdown, for example, Alfred leads the charge against the Viking line, while at Brunanburh, English skirmishers manage to disrupt the Hiberno-Caledonia-Norse shield wall sufficiently for Æthelstan and his retinue to lead a charge which breaks their formation and leads to a thorough rout. The point of this that English battle tactics revolve around a disciplined and tightly-knit shield wall, supported by skirmishers and a core of more heavily armed and armoured retinue warriors, and this was also the case at Hastings; in visual sources like the Bayeux Tapestry and literary sources like the Carmen de Hastingæ Proelio, we see the English arrayed atop the hill at Hastings in their tightly-locked shield wall. As a Norman, the composition of your forces would be significantly different. To start with, if you saw somebody on a horse, it was a good bet they were on your side. The Norman army in 1066 was far less infantry-contingent than the English, and tactics largely centred around heavy cavalry charges supported by missile troops screened by infantry.
With that said, there would also have been some visual clues to a sharp-eyed fighter if things did get chaotic. Guy of Amiens and William of Jumieges both remark on the English preference for wearing knee-length tunics, while the Norman fashion was for trousers, as well as the English proclivity for long hair and finely-groomed beards compared to the cleanly-shaven faces and closely-cropped hair of the Normans.