How To Quick Switch Weapons Like a Pro

No introduction! Let's keep this short and sweet. The secret is keybinds. You want your weapons on 1, 2, 3, 4, Q, T, Z and X. Personally, I'm set up like this:

1: Shotgun
2: Heavy Cannon
3: Plasma Rifle
4: Rocket Launcher
Q: Ballista
T: Super Shotgun
Z: Chaingun
X: BFG/Unmaykr

If it isn't obvious, keeping everything within reaching distance of the fingers already on WASD makes life a LOT easier than jumping around every time you want to switch to your heavy weapons. That's it! I'll add a couple more sections on gameplay tips that I find help me:

Just a preface and disclaimer before this section: I'm not SUPER good at the game. I have beaten 2016 on the hardest difficulty, and am having fun on my current and first playthrough in Eternal on hurt me plenty. This is generally aimed at people that are struggling to get started. Who knows though! Maybe this is the meta and I don't realise it.

Long range heavy hitting: Switching between ballista and quickscoping with the heavy cannon, potentially throwing in some multi-rockets with the rocket launcher.
Close range heavy hitting: As before, adding in Super Shotgun, flame belch, and grenades. Don't forget to switch grenades and use both kinds!
Fodder demons: 100% use the flame belch. If you haven't bought the upgrade which decreases flame belch ready time, consider saving it for fodder rather than heavy demons.

Hope this helps!