Withdrawal from both Iraq and Afghanistan. Insistence that a two state solution be immediately and actually pursued in Israel / Palestine. Diplomatic engagement; no unilateral military adventures; active participation in the UN. Address of Global Warming and Climate Change initiatives; real oversight and regulation on industry regarding environmental protection BUT ALSO real oversight and regulation on the financial / banking industries to disallow capitalism from eating itself yet again (of course, that's a tricky one for a number of reasons). Address of universal healthcare needs and to buck the insurance lobby in favour of humanitarian care of all people. Address of housing and education needs; tackling inner-city crime by addressing what life chances there are for young people (diverting them from gangs, etc). Address of the 'food products' industry (a la Michael Pollan and In Defence of Food) and a real food revolution to help deal with the obesity and health crisis in the US.
End extraordinary rendition and use of torture; close Guantanamo Bay; revoke the PATRIOT act; restore / strengthen civil rights; sign-up to the International Criminal Court and revoke the idea that America is immune from its remit. George W. Bush should be prosecuted as a war criminal for the invasion and occupation of Iraq (along with Tony Blair). Ensure separation of church and state. Allow for gay marriage or civil partnerships at the very least. These are a few of the more radical, but just, moves which Obama should also undertake.
These are just the first few things which come to mind. It's a large spectrum of issues, but all of them are achievable. What Obama must remember is that he has a huge mandate specifically for change and progressive change at that - there is much ground to cover, but huge enthusiasm to see it through.
Don't be sheepish President Obama - yes, you can: now get down to business!