i would like to give you some advice on the gun handling. Try to avoid pointing your gun upward, it's way more difficult to bring the gun into action when pointed upward then downward.
When doing building searches keep the gun muzzle about 20 cm low so you have full vision but keep the butt against your shoulder.
If you spot an adversary you just have to lift the gun and put your finger on the trigger to get a clean lineup of your sights and fire.
Don't mess with the safety, the safety goes off when you leave the vehicle or you start the search. Keep your finger off the trigger. Put the safety back on when the action is over and all threaths are neutralised.
Don't lean against walls, nor scrape the walls when conducting searches. Bullets tend to follow walls and you make a lot of noice when you scrape the wal.
Adjust the sling so the weapon sits against your shoulder and the sling is just long enough to move your gun to the ready position. If your main gun would fail under fire you can just drop the main gun (it will fall in front and across your chest due to the sling) and go for your pistol. Don't try to fix a malfunction while under fire, if you have a backup gun
Keep the weapon straight in line with your body, move your upper body to scan the area with the weapon. When you see a Target and wan't to neutralise it, shoot a few rounds center mass and only lower the sight just enough so you can look over the sight to the target. When you see any movement you go for a headshot due to possible use of bodyarmour.
Don't stand up straight, crouch a little to be more stabile, and always look where your muzzle is pointing.
NEVER point your weapon at your buddy.
When you are in a stairwell try not to pile up in a bunch. You have 3 different positions you should cover while beeing in that picture. And you form a beautifull target in that picture.
Stay away from open doors, never stand still in an open door, either go in, or cover the door from the side.
Always know where your buddy's are and where they are looking at. Practice the same position in the drill. Front man scans forward, second, third, fourth... man scan sideways, last man covers the back.
If you do a 6 man drill the second man can keep his weapon low and also toward the front.
Room clearing: #1 breaches door (ram, shotgun) , #2 goes in and left to the corner, #3 goes right and to the corner, # 4 goes left, #5 goes right, # 6 gets away from the door and covers the rear. When room is clear #1 enters the cleared room and breaches the next door. Always have the same place, know where YOU should go and what area to cover.
Use paintball guns instead of Airsoft, the painfull hit of a paintball gun will be more usefull in learning from your faults.
Airsoft guns look cool but they are way too difficult to identify from a real weapon, so when the local cops or soldiers show up they might not ask a question when they see you but they might neutralize you!
Paintball guns have a distinct look and are not confused with a real gun.
train like you fight, fight like you train
good luck
ps knives are cutting tools, keep them as sharp as possible as long as possible, you might need them later cutting free hostages or buddy's, so don't abuse your knife unless really needed.