Hardly would I recommend some other investment besides Bitcoin, but if you can afford to take bigger risks, you can play with some altcoins, not putting too much money into it, of course.
Best way of investement... how to be grow money like safe river. Trading on altcoin's just sucks one gambling no really better way to grow.
It all depends on how much you can take risks because all investment comes with some risks. For example, you can invest in few good casino bankrolls. Surely you can make some decent profit in the longer run. You can also lend money in this forum with proper collateral and never lend money without collateral then you can make some profits slowly and steadily.