There are many things that can be done on a marketing front. Moreover, marketing will be essential with cellular phones, because this is such a competitive market. In light of this, let me give you three suggestions of what I would do.
First, I would see what other successful companies are doing. If they are successful, they must be doing something correctly. More importantly, I would would not rest on their research or what they are doing or did, I would improve on it. This will create greater success.
Second, I would talk to people and do surveys to see what people want. I would want to see what people find most important to them. Do they want more data, more coverage, better pricing or something else?
Third, I would spend some money on forecasting the future. If a company can be groundbreaking and give this image, then you can win over a lot of people.