First you need to check that your listing is 100% compliant. You can not have any geo keywords in your categories. Also make sure you check the box to not show your address since people do not come to you.
If you don't check the box and you ever get a call from google to verify make sure you say yes people come to my business to drop off rugs.
Yes you should upgrade your listing to google plus.
SEO for places pages consists primarily of getting citations. Citations are your business name, address, and phone as they show on places page appearing anywhere on the Internet.
Just like back links there are different qualities of citations. Google top directories and get the list if the top 100 and start with those.
Other than that anytime you write a blog or article include a citation.
Here's a tip. When linking your website to your places page do not link the page your are optimizing for that city. Google now combines your organic listing and places page... But if you have a seperate inner page optimized for that city then you can have both appear on page 1.