You control at least one other creature that has at least one +1/+1 counter on it and that does not have summoning sickness.
Combine Guildmage does not have summoning sickness.
Mana Needed
({1} magic symbol) ({G} magic symbol) available.
Steps
Activate
Combine Guildmage's first ability by paying ({1} magic symbol) ({G} magic symbol) and tapping it, causing each creature you control to enter the battlefield with an additional +1/+1 counter on it this turn.
Activate a creature you control with a +1/+1 counter on it using
Kiki-Jiki's ability by tapping it, creating a token copy of any nonlegendary creature you control with haste that enters the battlefield with at least one +1/+1 counter on it due to