Travian has it's own codes of conduct that you can't exactly look up anywhere. If you've played in a good/premade team, you will likely know them already, but if you're new to the game or have only played with inexperienced teams, you might not be familiar with them. Which is why I've decided to put them down in writing. There will be some variance across servers and teams, but the following points will in general be agreed upon in most places.
Table of contents:
- Farming etiquette
- Chiefing etiquette
- Respecting "personal space"
- Auctions house etiquette
Farming is a key part of the game, and something that some people will spend a lot of time on. Naturally, there's dos and don'ts for farming, in regards to your own teammates.
Generally, people do not like "leechers", and teams will often have more or less defined rules about it. Farms are of course generally "public property". However, in certain cases, you should be mindful before sending your raids.
If you see a teammate scouting a juicy village that is not already being farmed - do not send your troops straight away. Your teammate is putting in the work to scout the map for new farms, let him/her have the initial reward, before joining in yourself. Wait at least 24 hours to see if they're grabbing the resources/clearing the village, or alternatively send them a polite message asking them if they're planning to launch on the village.
Speaking of clearing a village: if your teammate spends troops on opening up a village for farming, allow for some time to recoup losses/reap the rewards. If you see a teammate taking out troops in a new farm, let him/her farm it alone for at least 24 hours.
If you're the one who cleared a village, only to see teammates swoop in grabbing the resources soon after, keep in mind that they might not be aware of you clearing the village, especially not if you've sent a few raids so the clear is no longer visible on the inactive village. So while you might feel like sending an angry message, start off with a polite one. Explain that you cleared the village recently (maybe include the report), and would like to have it for yourself for a little while. If they refuse, you should probably contact one of the leaders in your team.
If you're chiefing villages from inactives, or taking oases, they'll likely have a bunch of incoming raids. Do not kill the incoming raids. Teams will almost always have rules against killing allied troops in chiefed villages, and quite often against killing any troops at all. Even if your team doesn't have a rule against killing non-allied troops on your chiefed village, it will be considered very bad mannered.
So, here's the right way to chief inactives: do not send a large escort with your chiefs. If the village is inactive, there's not going to be any defense after the initial clear. Just send ~50 troops or so along with the chief so it doesn't die. This way, if you aren't on to remove the troops straight away after chiefing, there will only be enough to kill a few raids. After chiefing, rename the village to something that includes "chiefed". Of course you don't have to just sit and accept raids coming in forever. You can either send an IGM straight away, or wait and see if you notice that some players keep sending raids hours after the name change. In either case, just let the raiders know that the village is chiefed, that you're letting the raids already coming through, but that you will start defending the village in XX hours/when all current raids have passed. Include the village link/coordinates in the IGM so it's easy for raiders to remove the village from their farmlist.
Respecting "personal space":
People generally don't like other players settling close to their villages, especially not important ones, without permission. If you're settling close to an unallied player, you risk getting catad/chiefed. But keep in mind that settling close to an ally might cause trouble too. So unless your two clusters of villages are naturally merging from the caps/spawn villages you have, drop your teammates a quick message and ask for permission before settling close to their cap/village clusters.
Related to above, you'll also have to think a little bit when you're looking for oases and nice locations to settle to have access to them. As said, you should ask for permission before settling within another players cap area. A large part of this is the oases. A capital village always takes priority for oases over non-cap villages. It's pretty simple - an oasis is far more valuable to a cap that can get higher level fields, than any other villages. If two allied caps happen to be settled close to each other and have overlapping oases, the leadership of your team will probably be the ones to settle the matter - it varies from team to team and situation to situation what the outcome will be.
Showing a little courtesy in regards to oases doesn't only apply to cap oases though. If an ally has settled a village in range of an oasis, before you move to the area, drop them a message and ask if it's okay to take the oasis (keep in mind that it's almost never worth it for ordinary villages (non-cap, non-15c) to take a 3rd oasis due to the high costs of HM20, so if the village already has two oases, it should be fine - never hurts to drop an IGM though).
Auction house etiquette:
If you spend some time (and silver/gold) on the auction house to pimp your
ride hero, there's some things to keep in mind. If you're bidding against un-allied players, go nuts. Outbid them, maximize their bids to make them spend more silver and so on. However, most teams will have more or less strict rules on bidding against allies.
The basic rule is usually that teammates shouldn't outbid each other, and shouldn't push prices. There are exceptions to this of course.
For the first days with auctions running, there's typically not really any rules, especially not for CP helmets - it can still be a good idea to communicate with allies that you're bidding against though, so the team doesn't use silver unnecessarily. An example would be that if you're willing to put down a much larger amount of silver for an item than your ally is, there's no reason for your ally to bid you up. This would take some credibility for your teammate to believe you though, so if you don't know each other well, don't get mad if he doesn't agree to let you have it without bidding.
However, once the initial craze has passed, it'll be considered rude to outbid teammates without warning, even if the team doesn't have any official rules against it. If you see that your teammate got outbid by an enemy player, it's of course fine to put a new bid. If you're in urgent need of an item (could be ointments or a bucket for example), it's generally okay to overbid allies too, though you should drop them a message and explain why. If an ally has bids on an entire page or two of ointments and you want some too, drop them a message and say so - perhaps they'll even be able to lower their bid so you can get them cheaper. This goes both ways - if you've bid on an entire page, be willing to give up some of them to teammates if they ask, and before getting mad if they overbid you without warning, check if they only overbid you on a few of them and not the whole page, and let them know that you'd appreciate it (and maybe even lower your bid) if they talk to you first.
Spiking is sending defensive troops/heroes to inactive villages that are being farmed, thus killing the small raid parties going there. A few people will say that it's just legitimate tactics and part of the game - but the majority of players and teams still frown upon it. Especially, you'll have some very mad teammates if you kill allied troops with spikings (and many will find it distasteful, even if it only affects enemy troops). You'll probably get yourself on top of the hit list for many big/powerful players if you spike, and your team might not want to provide you with support so... Don't do it.