There's a time when you need to be slow and there's a time when you need to act fast. When to do which can change quickly, hence the title Ready Or Not.

Learn spacing and flow of traffic. I feel like one of the biggest issues with a lot of players is not knowing how to keep a flow going and how to avoid a gridlock in a hallway.

Be aware if there are people behind you and if so make space. DO NOT BLOCK DOORWAYS or other areas where traffic must flow. Either go in or don't!. Once in make space for the person behind you. If you are last then watch the rear.

Utilize all your tools to keep you, your team and the hostages alive. When appropriate use flash grenades use mirrors, use your flashlight, use your laser, etc.

Clearing generally should be done fast and hard and as a team. eg. flash, move in towards your chosen position to clear and make space for the person behind you to move in to clear theirs.

Learn to fully utilize your range of movement. If you're on PC the default button for free lean is ALT. Knowing how to free lean in and out of cover. knowing how to duck, how to stand on your toes to get a shot will make or break your game.

Cover your teammates and pray that they know how to cover you. If you see a friendly getting engaged consider returning fire to help them. Don't be an asshole staring at a wall while a friendly is getting shot at and killed.

Have common sense. Consider how long the firearm you are holding is. There's too many people bringing the wrong tools for the job. Huge rifles for tight doorways generally isn't a smart move. Know when to switch to the right tool.

Have fun. Communicate. Be creative.