My very first business I set up at 14 years old was a yard care service. I actually started by going door to door in my neighborhood. I started out with 10 yards and in a two block radius. After two seasons of mowing at 16 I got a little cheapo truck and asked my customers if they could put my name out there so I could get some more business. My dad put my name out and what I was doing at his work and that's when I got a flood of business. I was mowing yards every day after school, and until dark on weekends. Now this is where the business I created takes the wild turn. I am a very big car nut. I love classics. I know how to work on them, no how to make more power, can trouble shoot, all that good mess. Well one day I was mowing this guys yard. He was a pretty well off individual. He was restoring 1971 Dodge Challenger R/T. I heard him messing with the vehicle as I was finishing up trimming around the drive way and I told him I could help him if he needed it. Of course he accepted and asked me what I knew about old cars. Well I showed him and he asked me to start helping on my spare time. I did, next thing you know I get a phone call from him. Hey, so and so is having a problem with their vehicle, would you like to check it out. That was it, I knew I was in business. Before I knew it and my parents knew it, I was making about a grand a week just working on cars in my spare time.
The point of my whole story is that if you want to get into that kind of business at a young age, you need to start getting clients by offering services that have very little risk of damage. Show them you can do a **** good job, and strike up a conversation with them. If you see someone who has a big fish tank for example, tell him you have one, and kind of give an idea you know what your talking about. Share experience with them, maybe offer them a piece of advice to get them on the hook. (haha fish joke) Have a sales pitch that doesn't sound like a sales pitch. You got the ambition, just need to figure out how to achieve your goal.