Google says local results are based on relevance, distance and prominence. Reviews are part of prominence.
Fill out your profile
Correct name, hours, phone, category, services and photos. Keep it updated.
Get steady reviews
Keep reviews coming in regularly and reply to them.
Have a website
Link a real website to your profile so Google and customers have more info about you.
Nobody can promise number one
Anyone guaranteeing a top spot is lying. You can only do the things that help.