Intelligence and drive are important, but they can both be cultivated and given direction.
To a certain extent personality of the individual child plays a part.
To a certain extent, realistic encouragement from parents to look to the future comes into it.
To a large extent, praising of persistence, determination, consistency, thoughtful planning of assignments, and good time management come into it. Praising effort, not final results of projects is very important because children become aware of effort and start to consciously organize themselves and become methodical in their approach to work.
Something along the lines of - "You seem really interested in the Tudors - do you think you'd like to study history in university? It could take you in many directions after you graduate - masters in library science, archival studies, teaching, TV news production, a lot of history grads end up in law..."
Or - "It looks like maths and art are your strong suits, DD. Maybe have a think about architecture?"
Keeping their eyes on the prize by reminding them of the future helps them stay focused on the day to day slog.
Staying interested in their creativity, interests, tastes in books, music, celebrities, sports, hobbies, TV programmes, movies, tiktok stuff, etc is really important too. They need to feel you are interested in them and 'get' them as individuals. Put their art on the walls.
I would also say parental/ family engagement with the resources the local community offers is important. If you see little competitions advertised - colouring competitions, poster competitions, poetry, etc, encourage your children to enter.
Going to the library in particular shows them that you value the life of the mind. I think children need to see their parents reading and being curious about the world. Having books at home makes them part of the backdrop of their lives.
You don't have to travel or spend money on trips to museums, etc.
Having conversations with your children about their interests, their friends, and what they're reading or listening to or learning in school is really, really important.