You can not force a heat, dogs go into heat 1-2 times a year most often every 6 months or so. Females go into heat on their own schedules, though it is known that some females in heat can cause another female to go into heat when they live in the same home. I have heard some people say that being around a female in heat sometimes helps if they do not live together.
The fact is while it may help there are no guarantees. A female will go into heat when she is ready.