If you use Twitter for business or professional reasons, include keywords in any tweets you want to promote.
An easy way is to pop in one or two keywords with hashtags: these are more likely to be found and retweeted.
For example, say you are about to run a workshop next weekend on bicycle maintenance.
Bad tweet that will only be noticed by chance:
"Yo Bikiebabes! Get together Saturday to fix those shonky 2-wheelers." (No keywords.)
Good tweet that will be found by more people and is worth retweeting:
"#Bike maintenance workshop at Adelaide Bikiebabes, Sydney St, 9AM Saturday. ow.ly/xxxxxx"