I want to invest short on the altcoin. what about you ?

For ICO investors this is the most common target where they can short out an easy profit by means of investing to these project but talking about on how to know an altcoin to come into the market then theres no guarantee but somehow you can able to know the updates on what is the team planning when it comes to listing and as being said by other members earlier you can actually follow their social media regarding on their recent updates and possible plans ahead.
Investing on the ICO may not be good for short term because most of the ICO last for at least 4mos now and the value of that token will still depend on the project. If you want to do short term, you'd better to trade on the coins that is already listed in the exchanges which is more convenient I think and you don't need to wait for months before you can sold that token, learn more about short trading this can be a risky decision of yours.