https://poloniex.com/ - tends to have more volume, lower fees but chart sucks.
https://bittrex.com/ - better charts. I prefer Bittrex for a variety of reasons but everyone has their preference.
If you're going to get serious about things then you should probably sign up at https://www.coinigy.com for their charting and the ability to set alerts etc.
And yes, you will lose especially if you trade on emotion, listen to all the hype on the forums and troll boxes etc. Stay disciplined, set out some rules for yourself and stick to them no matter what.
I agree, this two exchanges are more reliable to me because there many traders and turnover is huge. Volume are big enough to trust this both exchanges. I may also add to OP that do your own personalized research before you jump, be updated on each coins or cryptos being traded because this is your arm in dealing to start cryptocurrency trading.