Training is training. You're in the academy, you learn techniques and then you roll and try to execute the techniques you've learned against your teammates who're (generally) trying NOT to let you do the techniques because they're trying to execute their techniques on you! For some people, this is where they live. They go to the academy and train and look forward to the familiarity of their training partners and their respective games. For other people, they are looking for something else. They might be looking to test themself in a different environment against different, unfamiliar opponents. They might be looking for a different competitive experience. Neither is better than the other. They are just two different things. One can be a great academy grappler but that doesn't necessarily mean that the same grappler will have the same experience in a tournament. There are different skills that are needed to compete successfully in a competitive environment. As with jiu-jitsu or anything, some people will have more natural abilities in certain areas than others. In either case, those abilities can be practiced, developed and improved on.
Competing brings with it several different components than academy grappling. When you first start out, you'll most likely be facing someone you don't know or know nothing about. Of course, if you chose to continue to compete, you will become more familiar with the other people in your division and will likely encounter them again in your jiu-jitsu journey. But until you do it regularly, everyone will be new to you.
Almost all tournaments will have time limits or point limits. You will only have a limited amount of time to finish your opponent or get ahead on points. You can't just go another round or wait until you're in a better mood tomorrow. And unless it's double elimination, if you lose, you're done for that tournament (not counting any Open division).
There is a referee involved. You are not only fighting your opponent, you are fighting the referee too! Referees are like your parents. You have to make sure they notice when you do something good so you get rewarded for it. Sure people always say "Submit everyone so you don't leave it to the ref". Well, if it were that easy..... I don't know if anyone tries to NOT win. I think most people try as hard as they can. If they don't, then they need to work on that skill.
Conditioning for a tournament is different than academy rolling. Some people can roll for an extended amount of time at the academy. Competition brings a whole different level of adrenaline, anxiety, anticipation, excitement and exhaustion! The adrenaline dump you get from competition is different than anything you will ever feel at the academy. The anticipation of competing extended over an unknown period of time (typically lasting anywhere from 30 minutes to 4-6 hours) is very different than getting to class, warming up, learning techniques and then rolling. Trying to stay warm and prepared with no idea of when your turn will be is akin to some sort of Geneva Convention-breaking torture.
Mental conditioning is the least addressed part of competition training. Sport psychologists are used by many high level athletes. As this sport continues to grow, so will the importance of mental conditioning.
If you're just starting out on your competition journey, the first thing to do is to just go do it. See how it feels. Establish a baseline of what you experience and how you handle it. Now you'll have a starting point. Then each time, you'll develop and refine your process, your preparation and your execution. And as for your gameplan, just go do what you do. Afterall, that's what you do best!