About Foreign RelationsEdit
In GPS, there are two main indicators of foreign relations, the first being military, and the other being economic. These both affect you in different ways, as although a country may be unfavourable towards you on the military display, they can be favourable through the economics display. (Those filters are located at the top right of the HUD) Even if you are unfavourable in military terms with a country, being an economic asset to them can prevent wars, with that country, and if they're a member of the security council, they may veto the military intervention process.
Tips on how to create good Foreign RelationsEdit
One quick way in GPS to improve relations with another country is if you get lucky (well not so much for the virtual citizens), would be a natural disaster.
Flood the country with disaster aid. Via the AIDS - Disaster tab. Country standing should switch to dark green at this point you can arrange a meeting to sign at least a non-aggression pact, sometimes better with country movement for units. Quickly meet with the leader a few times and sign treaties.
Leave it 3 months or next disaster rinse and repeat and sign support or alliance treaty. Good thing to do as small countries at beginning of game with at least the 5 UN members. At this point i would assume you would be protected a bit by veto on invasion of other small countries. Worth a go
Also, if you're swimming in cash. Which unfortunately, is harder than it appears in this game. You can also donate money to another country and create trade agreements in their favour. This should help build up a more favourable economic alliance with the selected country.