The best way to multiply your profits you made from investing in Bitcoin is basically by investing it into Altcoins such as Ripple and Ethereum. Investing it in altcoins, you can easily double or triple your invested capital. But before you invest your profit in altcoins, you should first observe and study the altcoin market for a while. This will help you draw out patterns in their price changes which will help you maximize your profit potential. 

It doesn't matter how huge your profit is. The important thing is you were able to raise your funds. Now, it is up to you whether you want to multiply it or not. Having an extra $30,000 is already a big thing for me. Bitcoin is currently rising and I think it is going to be a good year for it so waiting can be a good option as well.

bitcoin is a crypto currency, a type of digital currency that uses cryptography to gain user access, manage units for making new currencies, and facilitate unit transfers from one person or party to another. Bitcoin uses a peer-to-peer transaction system and can be decentralized. When someone deals with Bitcoin, transactions are broadcast to the user's network to ensure this unit is not used more than once.
Bitcoin miners can benefit, because they will get a new Bitcoin prize that can be cashed. This is not an easy matter. For every transaction on the Bitcoin network (Blockchain), miners use super computers to find the hash. Hash itself is a product of cryptographic functions that connect blocks one block to another. In addition, Bitcoin has a currency unit limit of 21 million, so mining difficulties will increase over time.
However, by increasing interest in mining Bitcoin, alternative ways have also emerged to facilitate this activity.

You can multiply your Btc via altcoins trading.  Basically,  tou need to buy low and sell high.

I prefer buying alts when market decreases with at least 15-20% and sell when market recovers with minimum 10%.

I would not suggest anybody to buy altcoins. They are often found to be pumped up or dumped hard by groups manipulating them. Although the same cannot be said to be absent for bitcoin it still predictable to when bitcoin is going up or down. If you feel you have more control on the altcoin market then you should focus more on them.

However for a new trader I would suggest bitcoin buying every few weeks at a target buy range as soon as it is release and a target sell range to make the profit and keep the cycle going.