1) Generally I tend to lack military. What is a good general rule of thumb for how many soldiers to have in each city? Though I feel like no amount of soldiers can save me from the "stack of death" that often comes at me in Beyond the Sword.
2) I cottage spam. I build a cottage in every single tile except for resource tiles.
3) I generally don't pick people out who I do and don't trade with... I just trade with everybody. Is this a bad idea?
4) I generally have about one worker per city.
5) I feel like I don't expand that much, and yet, I feel like opposing settlers surround me so quickly that I haven't any room to expand. If I'm not going to be trying to claim cities via war, should I just build almost nothing but a bunch of settlers for quite awhile?
6) My build order is usually: warrior (to increase population), worker, settler. After that, I usually build some domestic buildings.]
7) I usually play as Darius. I like Financial and Organized, as well as the Apothecary.
8) Generally the only wonder I really go for is The Oracle (generally I grab Metal Casting with this, as it'll be the longest technology). Is there anything else I should try to place a priority in grabbing?
9) I don't really concentrate on great people very much (in any of my cities). When I do, I have EXTREMELY bad luck with getting the great people I want (for example, twice in a game where it said I had a ~95% chance of getting a Great Artist [I wanted a cultural victory], I got a Great Prophet :/).
1) You need to protect your borders first. Your large garrisons should be in border cities. The size of these garirisons should be based on your neighbors' militaries, so use spies/EP! If you are running Hereditary Rule, then this will likely determine the # of units in your interior cities, otherwise, I usually run 1-3 per city. If a city can't be attacked then it doesn't need defense. It is a good idea to have defensive and offensive units in your cities - and some siege for suiciding into AI stacks. Post Astronomy, make sure to build a reasonable defensive navy if you think that you might be invaded - it is much esaier to take out an AI stack when they are trapped on a boat! The same goes for bulding an Air Force later. Also, try to have a mobile stack to counter invading stacks, so know your enemies and put units in this stack that counter what they have - again, use Espionage!
2) Cottages can be great. A well cottaged capital under Beaurocracy can support most of you empire - but so can a Wonderspammed capital and specialized specialist cities, or hammer heavy production cities running Research/Wealth. Try to vary your cities more. Experiment and see what works for you.
Since you seem to be a builder at heart, you might enjoy a Wonder heavy capital. You need to have stone or be industrious for this to work well though so try a new leader! You can still cottage another city or two and run a gun pump at the same time.
3) The key to trading is not always who you trade with, but what techs you are willing to trade. For example, if you want to build Shwegadon Paya so that you can switch to Pacifism and generate more people and you dont have enough food to run many scientists, but you need one for an Academy or two, then DONT trade Aesthetics to anyone until you have the wonder. Also, tech straight to Literature and build the Great Library, but don't trade Literature until you have it.
On the other hand, be careful not to trade valuable techs to your biggest rivals if you don't need to. Never trade for back techs that you don't really need unless you know that the AI getting the tech from you is not a threat.
4) In a cottage heavy economy, you need to have enough worker to get the tile ready by the time they need to be worked. However, the real value of having more workers is to be able to change tile quickly in the mid to late game. I would recommend having at least 1.5-2 workers per city minimum in any situation. More never hurts - many player would recommend more. If you ever try to run a specialist heavy or hammer heavy economy, you MUST build more workers!
5) Have your worker chop out settlers and more workers quickly/ Use whipping more/ Be willing to kill someone/ Resign yourself to small empire economic stategies such as Wonder spamming your capital if possible, if not cottage the crap out of it. Either way, Buearocracy is your best friend, so defy any resolutions that would force you out of it. If you only have 5-6 cities, the you must start to specialize them. You need a gun pump! You also need one or two cities that can alternate between production/research and wealth/running specialists!
6) Getting an early library/temple up in your capital can be a really good thing for reaserch/great person generation, but don't build much more at the expense of losing good city sites! Unless you are running a strict WE or planning on killing someone, you NEED 5-6 cities quick (normally by 1 AD). On the otherhand, don't bankrupt yourself -a good REX stops when your slider hits around 20-30% (if you still want to go cottage heavy - specialists can help here).
7) Branch out! Since you are a builder and don't leverage Great People much, experiement with Philosphical or Industrious leaders. Try Ghandi or Ramesses.
8) Play around with the wonders - they all serve a purpose. BTW The Great Wall effects you power rating and gives you early EP and maybe a Great Spy. It could help you a lot!
9) Great people are GREAT! Try to learn how to use them/generate them faster. Read Obsolete's WE Walkthroughs!
I am not an expert, but play most of my games on Monarch/Emperor and these are the tips that got me there. I hope that they help.