i used to recommend to look where they are aiming, rather where the rockets are going.
sometimes jumping, specifically double jumping makes you very easy to predict.

join an mge server and

https://www.youtube.com/watch?v=SlCRfTmBSGs

whatever advice you may get, sometimes it's better to focus solely on dealing the maximum amount of damage and quantitatively weigh the amount of damage you'll receive off risk vs. reward.

it's a projectile that causes splash damage, and the majority of map structures guarantee a place for that rocket to hit you unless you run straight away. sometimes you have to suck it up, play brutally (there's no such thing as playing "disrespectfully" if your goal is purely to learn how to beat your opponent), deal a lot of damage & clutch the win with low health.

however you rationalize it, taking damage isn't a personal fault; video games are inherently designed to be accessible, so everyone is going to do damage to each other at some point. don't get hung up over it.

practice ammomod mge enough and you'll figure it out.

also, anyone who gives you shit for unintentionally playing clumsily/passive while you're trying to figure out the best method of approach is bad and irrelevant so don't worry about them. mge is specifically designed to help you figure shit like this out. with that said, refrain from justifying your loss to class-based differences when your intention is to overcome it. losing can be obnoxious, but learn to empathize with your opponent and you'll be able to handle many things in the game. chatting it up in MGE is a waste of your time. make the most out of your time and beat nerds up.

get a 120hz monitor

save your second jump until after they fire the rocket, so that you can jump away from the direction they're shooting at

hi i just played you a little bit ago
you always just do double jumps without airstrafing, its very predictable
try throwing in some single jumps
for the most part you have to use props or map mechanics to avoid rockets
definitely start airstrafing
find a positional advantage, or you will lose

most importantly

you have to realize that there is a radius around a soldier where he can fire a rocket and splash you no matter what you do. your options are to
a)never go inside that radius and win by staying at mid-long range and jumping/running away from his splash while dealing 20-35s. this is why badlands mid mge can be aids
b)jump around props to dodge/obstruct the rocket while dealing much higher damage shots and putting the other player on a damage clock.

option b is obviously better but it requires you to have monster dm and coordination

#4 is best advice so far. you should probably take most in-depth advice on movement with a grain of salt, it's honestly mostly just prediction and positioning. find the range you are best at and try to take most your engagements from that range but as #4 mentioned, sometimes you have to play risk/reward based on your health and you have to get in close for a kill. Usually getting close involves trying to bait out a rocket or even surfing into them

remember that the best spots for positioning (like on top of train, or a pillar) are also the most predictable. usually the goal is to force them to take those hard shots but also you have to bait those spots enough that they can't really know where you are intending to go

I tried airstrafing and it's pretty hard

aim is the best movement
that is to say it's easier and more useful to hit every shot than dodge every rocket

by bait i'm guessing like on the pillar at badlands mid a soldier might see me try to jump there, and he'll shoot there but i'll actually double jump straight to the bridge?

you can practice by playing on surf servers, but keep in mind you can strafe sharper in surf servers

a lot of newer scouts aim with their strafe keys which makes them really predictable. Its ok to use strafe aiming sometimes but getting better at actually aiming with your mouse will free up your movement and allow you to be more creative with your airstrafing and prop abusage. Since you said you're having trouble with airstrafing maybe you should play some surf maps to help you get the hang of it without the pressure of trying to hit your shots. Playing soldier against good scouts in mge/dm will let you see what it looks like when a scout is "hard to hit".

also obligatory

https://www.youtube.com/watch?v=eRrzY9K4yG4

That helps a lot with strafing, thanks!

if he had cratered...

It depends on your style but the one thing that is so effective it pisses me off (when I vs scouts on MGE) is when scouts don't jump at all, they just alternate between strafing in one direction for a long time and changing directions quickly at the right times, but it all does come down to seeing where the soldier is aiming. That's hard to know, though, if the soldier flicks a lot.

I have no idea how that works out in-game though, but I just jump and strafe wildly whenever I play scout.

lateral movement is pretty useless if you dont also vary the distance between you and the soldier, since then the only thing he has to think about is whether you'll go left or right

imo one of the most powerful options that a scout is making your time of approach/commitment ambiguous, which doesn't really have to do with lateral movement

that's the easiest way to bait rockets yeah but you can bait in a lot of way

Ground movement can be really strong if you stay at the correct range and use the map to your advantage. When you double jump unless you are stefan and can aim and strafe at the same time then your movement is a lot more predictable. Jumping is good to move around the map and gain height or position but if you play at the right distance and use the map to your advantage then you are much harder to deal with if you use the unpredictable movement playing on the floor gives you. A lot of new scouts just spam the double jump and a good soldier will find it very easy to just kill you as soon as you land. Watch some streams of top scouts and you will notice a lot of them play on the floor instead of jumping and if they do decide to double jump they will try and strafe in mid air to make themselves unpredictable.

just know your opponent and figure out their tendencies and play a mind game.

I like to use regular ground strafing, left right strafing, strafing in air forward and backwards, making it hard to judge rocket distance, just mix^ ur moves

scout v soldier ammomod is good for this as long as u can take getting 20-0'd constantly at first.