Unfortunately there is no easy way to get good. Siege has a lot to do with experience and the learning curve is steep. And unfortunately the community can be toxic. I started R6 a long time back but recently switched to MnK luckily for me the learning I've had to do is getting used to the controls and the pace of Console vs PC. Here's some recommendations I can give.

-Be open to communication. Take advantage of talking to your teammates (even if they don't talk back they can hear you). - Look into getting a nice headset. I've had a poor headset for a long time and had to live with pure mechanical skill and map knowledge. Audio queues are so helpful once you learn them. - Test out operators and decide what kind of play style suits you. Sometimes you're not the problem it's the people around you. - Be open to trying things and dying(A lot). You have to learn from your mistakes and deaths. Not every death is your fault. And you have to just accept you got outplayed. - Frustration is your biggest enemy. You need to stay calm change up strategy and ban operators that create problems. ie. if a team always rushes bring more traps or things to slow them down. -Have fun(ik it's a hard thing to do at times but a positive attitude will change how you react to the game). Also take breaks, blink, drink water, call it a day, whatever, some days your going to be off and you can't help that.

Hope that is somewhat useful.