It seems to me, perhaps from the comfort of my armchair and my ignorance, that the relative failure of the developed countries to improve the lot of the impoverished (via aid and development programs) is due, at least in some part, to failings of motivation, accountability and coordination.
propose that the UN establish a country-twinning program. Countries are ranked by need (if necessary, by an independent panel, although the required information is already generally available). This ranking by need will reflect the scale as well as the severity of problems. The 50% of countries with the least significant need, i.e. the "developed" countries, are then ranked on their ability to help (perhaps simply GDP?). Each 'helper' country is then twinned with the corresponding 'needy' country. The twinning ceremony can be televised globally, and if a little mystery or randomness is introduced into the process this ceremony may be almost as engaging a spectacle as an FA cup draw. In any case, the pairings would be well-publicised globally. (Every schoolchild, every taxi driver, every taxidermist, would know with which country they were paired... etc.)
Subsequently, changes in quality of life within each 'needy' country would be a reflection on their specific 'helper' country's commitment to help, and particularly on the scale of the practical (as opposed to ostentatious) financial assistance provided. Politicians in 'helper' countries would become more explicitly responsible for the plight of the impoverished. This accountability would provide a competitive environment which would motivate 'helper' countries to better provide and coordinate aid.
Existing aid provisions - which might see aid being delivered to non-twinned countries- need not be immediately suspended. Rather, aid currently provided to a non-twinned 'needy' country would be offset by a returned, equivalent* contribution from that country's twinned 'helper', directed to the appropriate other 'needy' country.
Contributions from charities could also be accounted for if necessary.
Re-twinnings every 10 years or so.
And if we want to get radical... I'll finish by allocating places on the UN Security Council on the basis of improvement of quality of life indicators in twinned countries.
* initially, at least...
(p.s. I'm sure this idea can't be new, but I've not found it discussed anywhere.)