$30,000 is not a large amount to "increase". If you want fast cash, I'd suggest stocks. But make sure you use a brokerage company to handle it. If you're not willing to do that, it's pretty much a gamble, but the profits can be huge.
On the other hand, if you want to put some work into it and no tlet the money work for you, invest it in a lucrative business. Asses what you like and try to turn it into a business.