I'm not sure if this really answers the OP's question, but it is a basic strategy that I use.
When speaking with players for the first time, I like to present myself as someone who's looking for a alliance where ideas are shared and spoils are evenly divided. My goal is to give the appearance of being a well balanced ally (not too pushy but not a pushover). In doing this I always bring multiple ideas to the table. For one, it doesn't allow the person I'm communicating with to single out a particular country that I may leaning towards attacking, and it shows that I'm the type of player that can make adjustments on the fly as the dynamics of the game change.
The two things that I try to figure out early on about the other players in the game are:
1) Are they leaders or followers in their alliances?
2) What is their level of greed?
Knowing where each player stands on those two questions allows me to gauge what kind of approach will be most effective in forming the right alliance.
If I have an alpha and a beta as neighbors, I may present myself as being stronger than the beta to the alpha, and less demanding than the alpha to the beta. Stronger players want someone they can control, but generally not total pushovers or players who may make tactical mistakes. Meeker players, while perhaps not minding playing a secondary roll, often don't want to be pushed around. Essentially, my goal it to present myself as the best option to all my neighbors while also appearing open-minded to the players across the board.
The level of greed a player displays can be used in multiple ways. The most obvious way is to present another neighbor as an easier target than myself. I've rarely run in to players that choose the path with no clear builds over one with obvious gains. A player's greed can also be used to influence them towards moving in a way that leaves them susceptible to attack. A player who isn't as greedy is more difficult to manipulate, but if I can prove to them that I'm the less greedy of their neighbors, it can influence them to join my side.