A lot of descriptions of Greek battles end with one side or another erecting a trophy but I've never read anything on what exactly these looked like or whether there was any upkeep of them. Would they have been maintained as a reminder of the victorious side's power or was it just a very temporary arrangement? Note I'm talking about battlefield trophies, not victory monuments set up later,e.g. at Delphi.
In most cases they were assembled from a standard hoplon kit (armor, aspis, helmet) on-site, and they were temporary (i.e. not maintained after the fact). They would have looked a bit like a scarecrow.
However for particularly noteworthy battles the tropaion would be upkept or replaced with a more permanent structure, like the lion at Chaeronea. I can't find it in my book right now but if I remember correctly, Polybius visited a few of those at ancient battlefields.