How can I make Civilization V more difficult?

You could play multiplayer, since the AIs will never be as good as a skilled human. You could modify the AI personalities to make them more effective (give them more focus on science) and you could just play 2v1 against AI opponents. You could also choose intentionally weak civs for a map, like playing Polynesia on a landlocked map.

AI difficulty settings don't really help much. The AI is actually quite stupid, and the higher settings simply add more cheats to it, which usually only results in adding frustration, rather than challenge.

However, if you're not against using mods, try the Smart AI mod. It's mostly just a bunch of tweaks, but it helps a bit.

You can get the mod through the Steam Workshop here: http://steamcommunity.com/sharedfiles/filedetails/?id=233424615

There are a few ways.. I'll go through a few:

1) Play versus Human players

For large strategy games like this, AI will always be flawed. Nothing is more challenging than playing against actual human players that can adapt to your strategies. Play with friends, or try joining/creating a lobby.. usually there are at least a few games going on.

2) Don't use tricks

If you want to win via science, culture, or diplomacy.. it's almost a guaranteed victory if you make everyone happy (so they don't go to war with you). If you don't use tricks to make them happy (ex: giving 1 gold per turn to each civ), they'll be more interested in going to war with you. Stop using these cheap tricks!

3) Try conquest

Conquest is harder than other strategies, especially if you start off conquering early in the game.

4) Don't play maps with a lot of water

The AI is especially retarded when it comes to the sea... they never buy a fleet (except for maybe Elizabeth), and their tactics when attacking through sea is so easy to overcome... play large land maps against the AI.

5) Limit yourself

I don't like using this option because it means you're purposely doing something you wouldn't normally do... but try playing a game by limiting yourself in some way.. examples:

• Play the game with only one city.
• Play the game without diplomacy (don't even accept embassies).
• Play the game with all AI players on teams.
• Use bad civs.

etc...

There's a lot of self-imposed requirements you can follow:

• Kill your warrior upon start - not fun with raging barbarians
• Build every wonder
• Pick some fights at inappropriate times (e.g. right when you start on the Pyramids)

Downside of this is that it's deteriorating your perfect, big game strategy, but it is fun regardless!

I think the best challenge is to play against actual humans. It would be best to play multiplayer with steam friends though. Just going to the multiplayer lobby and joining a game might make it too difficult to actually start a game, much less get a game going past 100 turns.

Multiplayer could then all play on deity level with raging barbarians, low resources and no start bias. This is also another reason why you should play with steam friends you know, since random players might leave if the game is too tough.