1. Focus on languages. I had the choice between becoming a tennis pro and going to university. I was a bit lazy, which made the decision to go to university a bit easier. But now I speak and write four languages, which is helping me enormously, not only as a coach but also off the court.
2. Choose one discipline. I didn't and I regret it. I was twice Belgian junior champion, one of my competitors made it into the top 20 in the world, but I grew up with football as well as tennis. My father was a World Cup player and I just couldn't let football go. My father coached the Belgian national team and then Al Jazeera Club. That's how I ended up here. I came to visit him. I had my flight booked home, but then I registered for a tennis tournament and won it, and I am still here! But my point is this: if you're good at multiple things, choose one; in tennis you need to make that choice at around the age of 11.
3. Believe in your family, friends and yourself. Don't worry about the rest of the rubbish around you; people not liking you or not liking what you're doing. Believe in family, then friends and save yourself until last, but that's important, too. You have to believe in yourself, otherwise it's not going to happen.
4. Mental strength is crucial. When things are not going your way, keep on fighting, show strength and character. Especially in a game like tennis, which is a duel with a player on either side of the net. It's not like football where you have support; in tennis you're alone, and sometimes in life you are, too. Keep on competing in both. There are so many tournaments: if you lose, forget about this one and move on to the next.
5. Listen to older people. I remember when my dad would say things and I would respond "Yeah, yeah whatever", but he was spot on. At the time you don't realise it, and you make a lot of silly mistakes.