how to reduce cost

I couldn't remember how to reduce cost,maybe we learned from last year.I didn't study anything with business by last year,therefore at the moment I no any ideas.But I must do it,if I don't ,somebody will hit me and leave some wounds to me.now I had to get a few deformities with my body.let me back to the topic.How to reduce cost.I only can guess 3 ways to reduce.
1) cut employes
2) reduce overhead
3) improve efficiency
I dont think these 3 ways is good for reduce cost,Just made points with my mind.if someone see my blog and doesnt confess my ideas,pleaes leave any commons which ways are much better.
Thank you a lot