Just to get things started....
First concern obviously has to be the choice of the tribe. I am afraid with the 5 (2+3) choices I got myself into a lot of trouble since this is really a tough decision.
It all depends on what the others choose - do they count on getting a good agri-tribe like Iros or Celts, are they just going for low-priority agri-civs (like Inca or Dutch) or maybe even no agri-civs at all and simply going for a decent other tribe?
The thing is, if we select a not-so-good agri-civ we risk that everybody else thinks so, too and maybe one team will actually get Iros then. Therefore I am in favour of selecting Iros as first pick, just to make sure nobody else selects them.
For the second choice we have to assume that some agri-civs have already been selected and only a limited amount is left. For that reason I am for Dutch as the second choice. They are, imho, the weakest agri-civ in C3C and for that reason there might be a decent chance that nobody else selects them. One thing is clear: Any agri-tribe is superior to any other tribe in the game. Also, the Dutch have one other advantage: Assuming that Iros get thrown out (or we would get them from our first pick), the Dutch are the only agri-civ that starts with Alphabet, thus there is a very good chance for winning the Philosophy race.
The alternative is of course selecting two medium-ranked agri-tribes like Sumeria or Maya as the first two choices. But again, who is to say that the other teams aren't thinking the same?
I guess it's fairly save to say that if we'd select Dutch as first choice that would be a fairly save bet to actually get it since there are 8 teams and 7 agricultural tribes which give the Dutch pretty good odds imo.
Anyways, first two are hard, what about the other three picks?
Whomp favours Riders which means China.
While I like the Riders as well, I think I'd prefer the Arabians since they also have 3 movement points but in addition cost 10 shields less and the Arabians have the stronger traits imho.
But Chinese sounds fine as 3rd choice, how about Arabia as 4th and I was thinking Japan as 5th since Samurai are a very strong unit and the traits are o.k. (could be better).
Decisions, decisions...