You can really help the Mars gameplay experience by reducing lag, which can be very frustrating to deal with as you try to shoot teleporting jets, dodge spazzing lasers, and dogfight unhittable opponents. All you have to do is follow these clear, easy-to-read steps, especially when you are the server host.
#1: Switch to "RDC" mode
This should be the first priority of the server host. Click the "server settings" tab and scroll down below the vehicle settings. You should see three dots under the label "Network Mode." "RPC" will be selected by default. Switch to "RDC" (the middle dot). This may greatly improve laser/vehicle collision physics. Note that if you hit "default settings" button, you will have to switch it back again.
#2: Close extraneous windows/tabs/programs
All players, not just the host, should be considerate and close other lag-causing applications whenever possible.
#3: Play In Fullscreen
Mars runs faster in fullscreen mode. Click "Game Settings" and you should see the "Enter Fullscreen" button. Alternatively, you can press "0" or right click the game window and select "go fullscreen."
#4: Set lower rendering quality
In "Game Settings," you can adjust the rendering quality with the arrow buttons. I recommend "simple," which doesn't look like crap and usually runs pretty smoothly. Also note the "interface" and "audio" buttons below. I disable the settings advisor and I usually have the music and sound effects off. If your lag is horrendous, you might resort to turning off the mini-map as well.
#5: Close settings tabs
Tabs are another little-known source of lag. The server host should keep them closed when not using them. (Thanks kruncher)
#6: Boot unresponsive/unproductive players
Each extra player in a server causes a little bit more lag. It is your duty as host to improve the experience of your guests, and if someone is not responding, or is disrupting the gameplay, or is simply not contributing anything of value, this duty may include booting the laggers from your game. Try to politely ask the subject to leave first, or at least announce your intentions and reasoning. If the player is NR or NC, make sure they aren't just "brbing" before you kick them.