Unlike Single Player games managing your empire and units in the order and within a short time can be paramount. To do so I suggest using the following settings:

Game Options

Interface Options

Global Actions

Quick Combat: Enabled, Quick Movement: Enabled

In single player you can afford pretty graphics because you have the time and luxury to do so between turns. When you're on a turn timer though and other players are making turns simultaneously you do not have the luxury to wait for the animations of a units to process before you can use another unit: not only will you be unable to properly position units if you do not have these options Enabled but it is very likely you will be unable to simply complete your turn as the eras continue to progress and you have to maintain more and more units

Auto End Turn: Disabled

I find this option to be particularly annoying because if a player desyncs and your turn auto-ends it will lock you out from being able to unready so that you can go back to micro-manage your citizens or production depending on how the turn so to avoid that issue in the first place I highly suggest Disabling this option.

Download Additional Content: Enabled

Particularly useful for Discord Groups because there may be specific mods which are standardized within those communities. I suggest you have this on so that if the host is playing with a mod such as BBG, Better Balanced Starts and so on you do not have to scrounge around to find it, download it, enable it, then finally be able to join the game.

Advisor: Disabled

If you're endeavoring to play in the multiplayer scene I do hope that you understand at the least the most basic of concepts of the game, assuming as much all this option does is add clutter to your screen which you cannot afford when trying to manage a massive empire within a short period of time

Interface Options

Auto Unit Cycling: Disabled

This is likely the most annoying option that is by default on in Multiplayer. If you are at war with a player and your screen suddenly shoots across the map while you're managing a vital position causing you to misclick and move a unit erroneously it could cost you that battle. Disabling this option is VITAL in Multiplayer

Key Bindings

Next Action:

I use this option to manage my Cities and Civilians. By tying it to a key you're comfortable using a lot such as an extra mouse button on your mouse or D as you see it bound in my settings above I can easily and quickly manage my infrastructure and city production

Next Ready Unit:

This option is specifically useful for managing large numbers of troops during wartime. When at war you can use this key (bound to E for me) in combination with the Next Action Key to manage your military and cities separately, choosing which ever is the most important to you at the time and circumstance

Alert:

This is an EXTREMELY important hotkey that not many people seem to be aware of. You can use this to instantly fortify a unit -- even if it has already used movement points -- as long as it you cannot see an enemy unit with the unit to get +3 fortifications.

Also this is useful for scouts so you don't have to check all of your units along borders every turn so that you can have out a scouting force and if a military unit of a civilization which you are warring shows up around that unit when you're going through your units it will pull you to that location and you will be aware of them

Attack:

This is useful for quickly attacking with many melee units -- This means any unit which takes damage when attacking -- when combined with the Unit Cycling Hotkey is extremely powerful for quickly attacking on a front.

However do not use this option for Ranged Attacks because if you try and they move their unit as you do your ranged unit will go nuts and run around in weird ways

You can use this with Airplanes and Bombers to quickly and efficiently rotate through them when combined with the Unit Cycling Hotkey when there are large numbers of them they become unwieldy due to the way they're set up and the limited time frame you have to manage them in multiplayer

Fortify:

One of the commonly used, I'll come back to you keys if you have a front-line and want to fortify it and focus somewhere else for a bit then come back to it this is one of the most common commands in your arsenal

Found City:

Mostly used for when you're in a click war between two players to get a city down this is your best friend. You're going to use this to found a city before your escort unit can be killed

Ranged Attack:

This is for all your units with a Ranged Attack, use this command so that you can quickly attack and fire with multiple units without them going crazy giving up their positioning

Skip Turn:

Use this to come back to an important area next turn without wasting much time this turn such as a front between another player with whom your not at war

Sleep:

This command is going to be used for Support Units, Great People, and Religious Units so that you can actually end your turn without having to mess with them every turn