How do you usually choose a money to invest in ?

[Jimmy_Zed]

Again, on bittrex when I click on the BTC-CND order book on the top, I can see a green and a violet part, both representing sells and buys of course. How should I read this ?

Those are subscripted with *Uses the top 50 levels of the buy and sell orderbooks
displaying the orders, which are a hint if people are currently in a mood to buy, or to sell. Bullish or bearish situation.
You get that in a more reliable way by a single glance at the candlesticks diagram.

Basically Jimmy Zed hit the nail. Microcaps, smallish coins are like featherweigth in the winds.

Cheers mate ! Just logical reasoning and a bit of experience - a couple of years to be more precise

[balu2]

coinemission (inflation), distribution, anticipated buy or sellpressure based on that and other factors

that's about it.

To be fair/clean is also required for the coin
  

[smalltimer]

check my sig if you can't make the good picks or have no idea how to read markets/make profit reliably.