Bad CS2 comms: "Two A!" (which two? which angle? bomb?). Good comms: "Two A long, one full HP, no bomb."
Three rules: tell teammates only what they'll act on, in present tense, with the minimum info needed. Past info ("they were at A long 30s ago") is noise.
Number + location + state. "Two B short, low HP" = teammate knows to push. "One A short, full HP, no AWP" = teammate knows to peek wide.
When in doubt, default to: number, location, weapon type. "Two banana, one AWP" gets a strong reaction from the team.