What will do it then if trying to rank in map packs?
Ranking on map packs is a mix of things really.
1. Number of citations
2. Number of reviews
3. Proximity of the address to the location
4. SEO Power of the original site (backlinks)
5. On-Page SEO within the website itself
6. Having the NAP printed on the website (Usually in the footer and on contact us page)
7. Placing a Google Maps insert on your website centered on your mapping location.
8. Displaying the same phone number on your website as the map listing
Some of these things will come naturally as part of your standard SEO, whilst others will require work in their own right. IMHO it usually takes a few months to start to see good results from a map pack SEO plan. The main thing with mapping is keeping every citation "clean" - that's to say you need the exact same address, name, phone number etc etc on every listing. With a map listing, Google looks for a strong correlation between your business and the location - every citation and the above list helps build this.
Also, and I really can't prove this to be honest but I've seen it work and it's one of my "go to plays". I always run an Adwords campaign in the locality I'm trying to get my mapping listing in. I can't really prove this works (it could be complete nonsense as correlation is not causation) but I've a strong hunch it helps a bit. At any rate if you're running a local business, bedding in an Adwords campaign and getting it profitable should be part of your game plan anyway. Most local businesses run away from Adwords because of bad experience with the "simple tool" they provide that's designed to earn Google money - rather than you. If you run Adwords properly and manually, you should get a nice ROI and low CPC after a month or two.