Hey and welcome to the world of rollercoasters.
My way to visit a new park is usually to stress everyone out because I am afraid to arrive late, than feeling excited when I see the first rollercoasters from afar and when I arrive at the parking lot I start panicking because I am afraid to end up at the end of a queue. This is also why I can never remember where we parked the car, I am just too excited to focus on such things.
Seriously now. I live in Cologne and even Mannheim is an awesome starting point to visit Parks, especially in France and the BeNeLux. My main advice would be.
1. When it comes to major rides I would check in forums or park pages if they are running. It would be a shame to drive for 3 hours when the major coaster is closed due to retracking for example.
2. Be sure to be on time when the park opens, especially now with Covid-Restrictions in Germany for example.
3. I usually visit parks counter clockwise and start with major rides in the back of the parks when the crowds are still queueing for rides near the entrance. This does not work in every park.
4. For parks you visit in the high season (local holidays for example) I would even buy fast lane passes when the journey was longer. If I was to travel to the US during spring break I would do so in order not to miss any coasters. Or I would even plan 2 days for a park.
5. Share your passion. Build a network with people who like your hobby. When I was 18 local forums helped me to plan trips and to get to parks. Of course you should always be careful and when you are under age always ask your parents.
6. Don't be afraid to visit parks alone. I know a lot of people don't like it but I even went to Orlando on my own when I was 24 because no one I knew had the money to go there. If you feel comfortable doing so, do it. I like traveling on my own and there is no shame in doing so.
7. Calm your FOMO. Even if it is hard if you miss a major ride, it is not the end of the world. There are some parks you will visit twice or even more often.
8. Check the plan and the homepage. Some parks have cool dark rides that hide behind inconspicuous entrances. At the same time try to avoid spoilers. Never watch the Kärnan or Mummy POV before riding them. I am still avoiding Gringotts POVs.
9. Travel responsibly. Respect local culture and nature. Try to travel as eco-friendly as possible.
I guess the advanced mode is checking which season pass offers you the best possibilities for new parks or parks in your area, I haven't figured this out yet. Before Covid it was always good to check Groupon for good offers for parks like Toverland, Heidepark and others.
Have fun and take care.