This note sets out situations where there has been no overall control in the House of Commons during the twentieth century. It considers precedents and conventions governing how the monarch might decide which party should form a government in such a situation, and when a request for a dissolution might be granted. It includes references to the Cabinet Office draft chapter of the Cabinet Manual and the evidence taken before the Justice Committee on 24 February 2010. The note also considers how a minority government or coalition might affect the work of Parliament. It looks briefly at the formation of coalition governments in Scotland and Wales. Lastly, it lists some sources of further information on situations of no overall control.
That is the best piece I know on hung Parliaments, prepared by Lucinda Maer for members of Parliament, from the Parliament and Constitution Centre.