Per capita wealth or total wealth? If per capita, median or mean?

Over what time frame? If you are planning for the next century, policies would be very different from policies for pumping the economy over the next few years. (Education is a great investment over the long term; it is just a waste of money in the short term.)

What powers do you have? Can you change human nature? replace the government?

Whatever your answers to these questions, different economists have spent much time and effort thinking about the answers. Yet you can see just how successful they’ve been.

You didn’t mention which country you were interested in. If it is a "developing nation", then the subject becomes "developmental economics":

http://en.wikipedia.org/wiki/Development_economics

For other countries, the subject is "economic development"

http://en.wikipedia.org/wiki/Economic_development

If you are really concerned about the long term, then you have to include ecology:
http://en.wikipedia.org/wiki/Ecological_economics

If you are interested in improving the lot of most of the people in the country, as opposed to just the wealthy few, then there is the distribution inequality problem:

http://web.worldbank.org/WBSITE/EXTERNAL/TOPICS/EXTPOVERTY/EXTPA/0,,contentMDK:20238991~menuPK:492138~pagePK:148956~piPK:216618~theSitePK:430367,00.html

BTW, what everyone agrees is that the single most important factor is the social context: countries where corruption is rife or property rights are not enforced tend to have far slower growth;

http://www.imf.org/external/pubs/ft/issues6/index.htm

places where diversity (racial, sexual, etc.) is accepted tend to have faster growth;

http://gregmankiw.blogspot.com/2006/03/corruption-as-impediment-to-economic.html

http://www.washingtonian.com/articles/education/1665.html

the higher the general health and education levels, the faster the growth; etc.

Less obvious, but well documented is that in the long term, bonanzas do more harm then good – whether we are talking about Spanish gold from the Americas or black gold today.