I'll give a slightly more generalized answer since you likely won't know exactly what kind of engineer you want to be, and that is totally okay!
First, continue to strengthen your math and science learning. Even if they aren't your favorite classes, their applications and the basics are necessary to at least get through your degree. Don't loose heart, the applications are much more fun and interesting than the tedious homework you have to do in high school.
Second, if you have the opportunity to be involved in a science & engineering fair or something similar I highly encourage it as an opportunity to explore your interests, build your resume, and practice researching and communicating technical understanding. A robotics club or state STEM competition or just building your own stuff and showing it around to different schools is an option as well. Take an interest in something and stick with it! There are professional engineering societies for Civil Engineering, Mechanical Engineering, Electrical, Aerospace, etc. If you go on their websites many have competitions, essay contests, and scholarships to apply for. Get involved early and you will reap the benefits.
Third, communication skills. Don't neglect english, debate, and all those soft skills. Most engineers will at some point need to explain how and why and what they did to either the public or the people paying for a product or design.
Hope this helps and hope you continue to follow your interests, we need more engineers like you to join us!
Maya recommends the following next steps:
From one engineer to a soon-to-be fellow engineer :), I encourage you to develop and nurture your curiosity about stuff. My feedback to you may sound a bit fluffy...but...one of the best pieces of work ethic that I think engineers bring to their work is their desire, their self-driven desire, to understand how things work and how to make them better. In many ways it is an attitude and maybe even a passion, like one may have for a sport or for writing or for a cause...it is an attitude that can support a continued focus on problem solving. A positive approach to problem solving can mean the difference between providing something that customer or client-partner has asked for...and something that a customer or client-partner didn't know they needed until someone like a great engineer designed.
Lots of words....what I mean to convey is that in your years during high school and beyond you will be asked to complete assignments big and small. This would be as good a time as any to practice asking questions borne out of your own curiosity and/or providing answers that demonstrate that you can "see a bigger picture" than what may be presented in an assignment. Of course, don't forget to do what is actually asked of you...that is step number 1 :) but be thinking about how what you are doing could be done differently. Differently could mean faster, deeper, more collaboratively (within school rules of course). Faster, deeper, more collaboratively...these are key tenets that can and do make engineers successful regardless of what type of job they have. These tenets also tend to exceed expectations of customers and client-partners which is also a plus!
I wish you the very best of luck. Always room for more great engineers!
I suggest that in high school you begin to think like an engineer and learn to communicate engineer principles. For example, if you have learned about the laws of motion (Isaac Newton's laws) in a physics class, you might try helping a younger sibling or cousin or friend to understand such laws in every day situations, such as why the book on the dashboard of a car slides from one side to the other when making a tight turn. Or, you might teach someone younger about optics and how a telescope works. By teaching what you know, those principles will become part of the way that you think and perceive the physical world. You can also develop spatial thinking by studying a map and tracking the route in your mind before driving to a new location as opposed to having a GPS map tell you directions as you go. Thinking spatially in this manner is a skill that will help engineers to think through complex issues and be able to effectively communicate. You also might try and use pencil and paper as often as possible to sketch out ideas and problems. Working through problems on paper, even if it is a math problem that you know the answer to, will help you to develop the thinking processes that are required of engineers.
All the best,