To echo PremEx, flying a lot does help.

Kidding aside, and more specifically, the answer depends on how much flying you plan to do, where, how (class of service, fare paid, ...), your preferred airline(s) if any and other particulars. Once you narrow those down you can get more specific answers. Also, if you plan to focus on one or a few airlines (always a good idea, if your travel patterns permit) you can find lots of information in that airline's, or those airlines', forums.

Many of us also do "mileage runs," especially when a relatively small expenditure will help reach a milestone that carries substantial benefits in terms of bonus miles, status (which can mean more bonus miles in the future) or something else we want. Check out that forum for more on mileage runs.

Good luck!