The objective of Peoples is to group your tribes into settlements. However, you don't have an unlimited number of tribes but must group your tribes with other players' tribes. Also, you don't have unlimited time to do all the movements yourself but must rely on (and take advantage of) other players' movements. In addition, the short-term value of a settlement is limited to its relations and advances so you must optimize this as well. Least, but certainly not last, the long-term value from a settlement is limited to the ages where you actually have a majority in it.
Let's look closer on all those limits.
The number of tribes
You have twelve subject tribes and twelve ally tribes in each age. The first age will se 12 villages of 3 tribes each, the second age will see 9 cities of 6 tribes each and the third age will see 6 metropolises of 9 tribes each. This means that grouping all tribes together will yield 4 villages, 2 cities and 1 metropolis - enough for a decent score but not for a winning score.
Instead, you need to maximize the point from each individual tribe. The first and simplest way to do so is to have all your tribes in settlements and have all settlements contain your tribes. This will earn you at least 1 point per tribe but more importantly, it'll give you a chance to fight for the majority in all tribes.
A majority can be accomplished using your subject tribe only (safe but expensive) or using your ally tribe as well (risky but cost-effective).
Settlements with own tribes only
Settlements with subject tribes+ally tribes
Although it doesn't change much for villages, the use of your ally tribe (and some risk-taking) is an effective use of your tribes and can yield a lot of victory points. The risk can be mitigated by having your subject tribe near the top of the stack, since the top-most tribe will break ties. This gives the following strategic guidelines for using your tribes:
Identify areas where your subject and ally tribes are close.
Move your ally tribe (or other tribes) to your subject tribe, to keep your subject tribe near the top.
The movement of tribes
Some general movement guidelines have already been touched upon above. This part of the strategy guide aims at the timing of the movement.
From the starting position, the first movement a tribe makes will bring it adjacent to either 1 or 2 other tribes. At lest two more movements are required before a village of 3 tribes can be founded. To move all the tribes yourself will take time but if you can continue other players movements, you will save time. This means that you should be very attentive when other players move either one of your subject tribes or one of your ally tribes.
In the following examples, a player before you have moved A southwards.
1. If A and B are your tribes, you can move A to B. If the other player tries to move C closer to AB or vice versa, you can move C to AB, ensuring that your tribes are closer to the top to break ties in your favor.
2. If C and D are your tribes, moving D to C may help the other player while moving C to D will protect your tribes from being used by another player.
You should also bear in mind which tribes the other players move closer and draw conclusions on which tribes they play. In the first example, if the other player's subject tribe is C, you cannot move AB closer to C yourself, since that would enable the other player to move AB to C and get C closest to the top. Instead, you should find other tribes (not played by any other player) for the completion of the village.
The guidelines apply to the later stages as well - settlement are bigger and movements longer but tribes will still move closer to each other. A special case apply when settlements start decreasing in the third age. If you have well-positioned tribes (many and/or close to the top), you should move tribes to it early to prevent it from decreasing. If you have less well-positioned tribes (few and/or close to the bottom), you should move tribes away from it to free your tribes for better use.
To sum up, we can add the following strategic guidelines:
Take advantage of other players' movements.
For each of your tribes, determine whether it's good where it stands or whether it can be of better use elsewhere (Age 3).
The short-term value of settlements
All settlements are not equal - their values can differ significantly depending on their relations
and civilization advances. Should they affect your strategy and if so, how much?
First a word of warning, don't focus too much on the value - it's usually better to grab two
low-value settlements than aiming for a high-value settlement. However, if given the choice, you
should look at the value of the settlement. Generally, a settlement is more worth the more relations
it has while the advances differ. Here's my personal rating of them, starting from the bottom.
Civics: A weak advance as victory points are shared among all tribes.
If you don't have any better move, try to get a citizen into a Civics settlement to get your share.
Culture: An average advance that scores higher the more players there are in the game, since that
usually leads to more different leaders in the settlement, but it requires relations that the other
players are not likely to help you with.
Religion: Another average advance where you will have to build the relations yourself.
If the settlement is or can be related to other settlements with your tribes,
it's worth your attention, otherwise not.
Military: A dark horse. It can mess up other players' scores but will also discourage them from
building relations with you. Claim military settlements if they already have many relations.
Economy: Another dark horse. Other players will be encouraged to build relations with you but
only if they also have economy.
Science: May be a low-value advance in the early ages but since you can actively seek settlements
with many relations, the score can get high.
Remember to also take into account the geographical limits to your relations. Settlements in
Oceania usually build few relations in the early ages, as do settlements without coast.
At the end of the age, you can further increase your score by optimizing your relations.
In some cases, it's best to relate your own settlements (Civics, Religion, Culture), in other cases
you should seek other players' settlements and assess whether a relation benefits you or them the most
(Military, Economy, Science). However, don't forget to consider the long-term value as well.
The long-term value of settlements
With new subject and ally tribes, can you plan for long-term value at all? Yes and no. If you can
get your future tribes into small settlements one age, they have a heads-up in the majority race in
the bigger settlements in the next age. However, as discussed above, you must struggle to optimize your current
subjects and allies so trying to include two more tribes will be very difficult. Also, your future tribes
may be played by another player in the current age so you risk helping an opponent. This risk is greater,
the more players there are in the game.
Nevertheless, there are some things you can bear in mind when planning for long-term value:
If given the choice, let a future subject tribe be the complementary tribe in your settlements.
If planning to claim the same settlement in the second age, prioritize coastal settlements as they are
more likely to grow. (In the third age with its unlimited movement, coasts don't matter anymore.)
If you expect to keep a settlement in the next age, choose an advance for it of more value.
If you expect to lose a settlement in the next age, choose an advance for it of less value.
If you expect to claim nearby settlements in the next age, build relations with them and choose advances that will increase their value, such as Economy.
If you expect not to claim nearby settlements in the next age, choose advances that will decrease the neighbors's value, such as Military.
To sum up the long-term value, the sixth strategic guideline is thus: if it doesn't interfere with your other strategies,
optimize the long-term value for settlements you keep and suboptimize the long-term value for settlements
you don't keep.
To sum up the overall strategy, maximize your advantage of the other players' actions and
minimize the advantage other players get of your actions.