Who do I farm? 99% of the time you will want to farm the castles of players who have quit the game. This is because they will have no, or minimal defences and will not attack you in return. There is no point in farming a castle if you're going to have to farm another castle for the rss to replace the units you lost farming the first castle.
When selecting targets consider first their level. A reasonable result from a raid is 15k, approximately 5K gold/5K iron/5K food. Castles below level 30 are very unlikely to have this much. Sometimes you'll find one as low as level 28 but below that they will have left the game before building up their warehouses and barns to hold enough.
The second consideration is if the castle is in a league. If you have seen that these castles haven't leveled up for a reasonable amount of time (a couple of days for castles below level 45, a week or more for higher levels) then you can check the league to see how active they are, if they claim to boot inactives or have a high ranking. If it looks like a dead or weak league then send some scouts and check it out. If it does have armies out then you might want to wait until the pvp global quest before you start using it as a farm.
When should I attack again? 24 hour period rather than an ingame day. Avoid attacking the same castle more than once a day or you might find you get nothing in return.
Tips for farming:
- Always scout first, just because you haven't farmed it recently doesn't mean that someone didn't hit it an hour earlier.
- Only farm the good stuff. You have a limited number of raids per day, make them count. Non rrs farming attacks can still be made once you have run out of attacks so leave your aggression at the door until then.
- Go long. Looking only 20km away from home is a waste of time, your range should be at least 50km, and if you leave your pikemen and dwarves at home it won't take you an hour to get there.
- Don't send everyone. Just send enough to get the loot and bring it home. If the empty castle you're attacking only has 25K in rss there's no point in sending enough units to bring home twice that.
- Defence can farm too. Save time by sending your defence out to farm. They shouldn't be facing any enemies so what does it matter that you're only sending 10K in attack power?
- Group your speeds. If you only have enough units for two farming forces then try and split them into a fast and slow group rather than two slow groups. That way the faster ones will get back sooner and you can send them out again.