Amelia,
I'm not very aggressive (for lack of better word)
I am just not a born sales person - perhaps you're not either? But I love playing the piano
and I love teaching it. I think I love playing it a lot more than teaching - but teaching is very rewarding too.
Some things that I've noticed that have helped me get more students is:
1. Always having a card on me - and giving it out to someone I need to put my number or any information on a piece of paper by writing it on back of card.
(In other words - our discussion is not about music - but I need to write something down for them.) A lot of times they are surprised I teach piano - and I have had people express interest in taking lessons from something like that!
2. In the winter I wear piano gloves - I had someone want to take lessons from me - just by that - In summer I wear music tops

It works! I didn't start doing that so I'd get students - I just like to wear stuff like that, but I've noticed they are unintended advertisement.
3. I like to study my lesson plans and get them ready in a coffee shop - I have had a lot of people ask me about music and piano lessons there.
4. Show a genuine interest in people - ask them if they play a musical instrument - Many times you find they have always wanted to play the piano.
Now - granted - doing this alone - will not fill your studio, but you will be surprised at how many people will just want to tell you about themselves - and start taking lessons from you.
Don't forget to play the piano whenever possible - not to show off - not for any ulterior motive - just out of pure joy. And people will be drawn to you.
I once was in church - and just wanted to get away from everyone and played the piano that was in a room that was being used far away from the main rooms. The room was dark, and because I didn't want anyone to know where the music was coming from -I just did not turn the lights out.
I had a friend come in - and tell me they were wanting their daughter to take piano lessons! I was shocked - I said - what kind of advertisement is this -playing in the dark? with a laugh - and she said - I think it's good advertisement that you don't even need the lights. (Not exactly a marketing technique!)
My point is - incorporate your playing in your life as much as you can out of the sheer joy of playing - and people will follow you. But don't do it so they will follow you - let it be a by-product.....