ETF Help

Hello Monkeys,

I'm a third year economics/accounting major and also in the process of reading Intelligent investor but I consider myself highly uneducated when it comes to investing. For this reason, I want to start off by not selecting one individual stock in my portfolio due to my lack of analytical knowledge as well as low capital.

I'm considering making my first investments in ETFs.
I'm 20yrs old so I'd like to say I have a high risk tolerance and want to hold for a long time horizon. Hence why I've been thinking about the Vanguard Emerging Markets ETF (https://personal.vanguard.com/us/funds/snapshot?FundId=0964&FundIntExt=…) as well as a Clean Energy ETF.

What are some things I need to consider when picking ETFs? And what else do you feel I should know? What other ETF's would you recommend?
Also - I'm under the assumption that ETFs are better than mutual funds due to ETFs relatively low costs and typical mismanagement of MF's.

Thanks