Currently, most IRC clients do not do much to visually and/or semantically distinguish sent and received messages. The only indication is the nick attached to a message.
A preference (perhaps off-by-default) to distinguish the two would be nice. A simple approach could be to make sent messages float to the right side of the chat window instead of the left (or vice versa for RTL locales).
Idea discovered via https://w3c.github.io/raur/#distinguishing-sent-and-received-text-with-rtt
-- Seirdy (https://seirdy.one)