Depending on what you mean by best investment.
Best Return, often highest risks: Derivatives, such as options allows you to enjoy upside/downside gains of equities with significantly less capital. However, options are just as risky as they are lucrative, especially if you are selling them.
Lower risks: you can invest in equities/ funds just as you would with a larger sun of money.
Lowest risks: mutual funds, gov securities, and etc.
Essentially, you can invest a smaller amount of money the same way as you would with more money. Difference is, your small capital disqualifies you from hedges funds, real estate an other capital intensive investment vehicles. Also, since it's smaller sum of money, you may be inclined to invest in riskier ways.
My last investment was an online store. And Im happy about that. The most difficult part was to find a reliable webhosting provider. But I did it.
https://zomro.net provide SSD ans stable services on reasonable prices with quick support to your queries.
In sum, best investment strategy should be determined by your personal risk preferences as well as return expectations.