Set up an international court, issue legal edicts to freeze assets of any dictators judged to be in contravention of an international (not US/UK) definition of 'human rights'.
Refuse to do business with dictatorships, rather than selling them weapons and doing 'under-the-carpet' deals between large corporations and those nations with tacit governmental approval.
Actively support exsiting democratic governments, even if that means US corporations lose some of their profits.. (see Venezuela).
Stop driving third world nations into poverty through aggressive IMF and World Bank/Free Trade/IPR (Intellectual Property Rights) agreements which simply destroy the local economies, again for the benefit of western corporations.
Allow third world nations to either produce or buy generic alternatives to Aids drugs etc when they cannot afford to buy at the inflated prices charged by western pharmaceutical companies.
All these measures and more will have a profound efect on the way the world views the west and the US and UK in particular.
Currently, the US has refused to join the International Court, blocked the sale of cheap AIDS drugs, sidelined the UN and either opted out of, or actively opposed most initiatives of this nature. This stance can usually, if not always, be traced back to powerful industry lobbies in the US.
And, don't fall for the trick of letting the US/UK set the agenda, i.e. 'Why Don't we go in and try to wrest power from Sadaam the evil dictator'
The question might be rephrased as:
'Haven't we learnt from the last hundred years of history that going into Middle-Eastern ountries and installing puppet goverments has yielded nothing but dictatorships, repression, despair, misery and instability, why do we want to do it again?'
And do NOT fall for the moral argument, which is laughable to put it politely..
How would the US react/vote in the UN if Russia decided to go in and liberate Iran on the same basis? (Or indeed any other country)
It is against the UN charter to invade sovereign states.. otherwise we open a Pandora's box and every contry with an agenda will be doing it in the name of 'Truth, Justice and the (insert country's name here) way.'
The US is currently the most powerful country in the world, it should lead by example, not through the use of military force.
That military might should be used in the defence of the principles of democracy and freedom, not as a blunt instrument to further the geo-political ambitions of power-crazed individuals.