With some practice, patience, and a willingness to learn and improve, you'll get better in no time.
If you want to improve at PUBG and reach a high level, you will need to make sure you get more out of your sessions than you might already. You need to start working on your fundaments, the most important probably being aiming. There are several ways to focus on improving this aspect.
If you want to get more chicken dinners, it's time to start working on that aim. You can use an aim trainer program to get better; you can even fill the wait times during your PUBG sessions to quickly switch to the aim trainer, for example, while searching for a game, waiting for the plane, or sitting around lobbies. Use this time to get a training session with 3D Aim Trainer instead.
Essentially, the free 3D Aim Trainer is an all-purpose training program to get you better at PUBG and other FPS games. Here are some aspects to focus on:
Target Acquisition
From the Become a Pro section in 3D Aim Trainer, pick Switching and Clicking training modules. Do exercises that have you follow the targets. Practice your general aim and work on your target acquisition. Even if you don't have the exact same guns like in PUBG, 3D Aim Trainer can import your settings and game feel to help with that. The majority of the mouse movement you do when you lock onto an enemy is done without needing your gun.
When an enemy suddenly comes into your view, you will most likely move your mouse first and then you will use the movement keys. That flick before the WASD movement is what you need to practice, and you can do that with the various flick modules in 3D Aim Trainer.
Practice your ability to track moving targets, as that will be the most common way of battling in PUBG, even at long range. Anticipating the movement and where to position your crosshair are crucial to reach a higher level in PUBG.
General Movement
While going around and looting in PUBG, do not focus on just picking up items, but always think about your movement. Try not to be touching any wall, door, door frame, or other obstacles in your path. This can be challenging in PUBG, as the environment is pretty littered with many objects and the doorways are narrow. Try to improve your speed and agility in confined spaces like this, so that you can get out of danger quickly or hunt someone down faster.
Every time you stumble into an object, a wall, or touch a door frame, you're slowed down, so if this happens often you will get killed more frequently.
Another trick to enhance the smoothness of your movement in PUBG is making precise turns and staying in control of your mouse/controller. If you have a hard time with this, you may need to increase your sensitivity a bit.
Even with empty buildings, you can practice good movement and peeking while entering them. Clear corners, rooms, peek down corridors, and so on. Step back and peek before you enter. Doing this will not only make you less likely to get surprised by a hiding enemy, it will also prepare you for a "real" encounter in buildings where you know there is another person. With good repetition you'll grind out this in PUBG, and it will become natural.
PUBG Tips & Tricks
Image from Reddit
Best attachments: Scopes
Even if you can get your hands on a sniper rifle, you can't really play at long ranges without a 4x scope or an 8x scope. Your line of sight will drastically increase, and you will be able to cover a much bigger play area. You can even scout out ahead, too.
Supply drops have the best gear
Speaking of sniper rifles and best gear, if you want to acquire them, you may have to risk it by going for supply drops. Get a vehicle to make sure you get it on time and do your best to outplay everyone else.
Best PUBG melee weapon: pan
Yep, it still has the most damage in the game, and it's bulletproof, granting you a little bit of protection from a certain angle.
Always wear a helmet
Never forget to have some protection from headshots. Durability is very important especially for longer fights.
Are the doors open?
Doors are closed by default in PUBG, so... if the doors somewhere are left open, someone either has been through the area, or they are waiting inside for you. Consider closing the doors behind yourself to mindgame enemies.
Practice driving
Get a good hold of driving controls; CTRL+1 puts you in the driver's seat, and the numbers up to ٦ cycle to the other seats. Shift gives a speed boost at the cost of fuel, but it can be helpful to get up hills.
With those tips, you should be on your way to win more often in this battle royale game. But keep in mind that it will still take a lot of patience, practice, and aim training, so make sure to keep up with your training sessions.