I had one more question, how do you even tell that how much those coins will rise.
I suppose if people are buying at start will make good amounts of profit ?
It's simply a case of demand and supply, often ICOs sell out within a matter of minutes due to the very high demand for the coins. When they are then listed on the exchange there is an excess of demand over supply and thus the price rises. With regard to how you can know by how much the coins will rise it is nye on impossible to be exact. Generally the more popular the ICO the more chance there will be that the coin will do 100% or more.