The fundamental growth factor - users
First up it would be good for us to define what growth means. This could be revenue, number of users, reduction in complaints. Pick a business metric. When you peel back the onion and look under the hood there is one thing that stands out about all others when it comes to growth... Number of new users of your product or service.
Granted you may have a leaky bucket (as a client and I discussed yesterday). Spring a leak and when you pour water in the top it'll never fill. Yes, you have to fix the holes in your bucket. Your bucket is your product, service and support. You need a good bucket.
If you have no users then none of this matters. Users are your life blood. Everything builds from there.
Fill your bucket.