Yes, I meant Prince to King.
I usually build really tall empires, with the highest pop in the game and only 5-7 cities. My most recent game on Prince was a breeze, winning as Napoleon in 1920-something?
I already practice luxury selling (and strategy resource selling to distant civs, wise or not). I almost never go to war, and I keep up with tech relatively easily. My greatest downfall is usually a small army and poor diplomacy with other civs. For some reason, every time Ramesses is in one of my games he hates me and DOW's on me at least twice.
Looking for advice mainly on how to balance things, because if I focus on war I fall behind in tech, and if I focus on culture or tech I fall behind in military, and no matter what everyone but maybe 2 civs hate me (I play on Standard/Large maps).
Do you build a lot of wonders? If so, that will definitely put a bind in Ramses' shorts (did they wear shorts?). He's all about wonder ho'ing. He's also one of the least friendly and tightest civs, which don't help either.
If you are good at staying even or ahead in tech, then you shouldn't have any problem with building a military strong enough to deter most others and defend your civ. Just build or upgrade the latest military units in large enough numbers to keep the heathens at bay. You don't have to have huge numbers, when you have a smaller area to protect and advanced weaponry.
Take advantage of mountains and narrow passes between them, bodies of water, forested hills, whatever you have available to strangle enemy movement and give yourself the advantage if they try to attack you. Even if you don't have mountains to block with, if you have a river to make a stand on, that helps- especially if you have hills or forests for cover on your side. Find places like that, and clear forests away on the other side of the river, so your enemy has no cover. Create kill zones to lure them into. Use extra Great Generals to make Fortresses with in key defensive bottlenecks or wherever makes sense- they are humongous for slowing and bleeding out large enemy offensives.
Build helpful defensive wonders (Heimeji Castle, Kremlin), defensive social policies (Tradition-> Oligarchy, Freedom-> Universal Sufferage), and build every kind of wall/castle/etc. that you can. Don't neglect aerial defense- keep the latest fighters and anti-aircraft guns available in plentiful supply in forward cities. Bombers can be great for defense too- build or buy them in a city with barracks/armory/Brandenburg Gate, and you can have a protective umbrella of bombers with 2x anti-ground (or sea, if appropriate) promotions and repairs between flights too. And of course get nukes as fast as you can, nothing deters an invasion force like being turned into vaporous radioactive dust. In small-civ games, I don't breathe easy until I have them.
And there are some civs that are better for making a stand with, like Ethiopia, for instance, with their melee units which are stronger when defending. There are pantheons and religious beliefs that improve defense, too. Have your head in the clouds if you like, but keep yer butt in a concrete bunker.
I could spend pages trying to explain defensive diplomacy, but the gist of it is, be very careful who you befriend, and when. Don't be lured into random wars in the hope of making friends, your erstwhile 'friends' will be as likely to make peace unexpectedly and leave you hanging, or turn around and denounce you as a warmonger just for helping them. I avoid most DoF requests, and stick to trading and embassies. Remember that just because you've been buddy-buddy with that big runaway and they've even exchanged Christmas cards with you recently, doesn't mean they don't have lust in their hearts- and don't expect dinner and a movie.
The only things you can really depend on in this game, are concrete, cold steel and uranium. For the best tool to help you survive diplomacy, get the InfoAddict mod and use it. Anytime another civ pops open a diplomacy screen unexpectedly, and you don't know where they stand with everyone else and what you should choose to do, simply click on the handy 'InfoAddict' button in the corner of the diplomacy screen (a feature the devs should be flogged for not adding from the start), and you can see exactly where they stand, who they hate, who hates them, who's at war, etc. I won't play without it anymore.