It depends on the way how you are at your managing skills and your analyzing skills. The process to accomplish a successful ICO includes many tasks and if you are confident enough about the value of your coin then you will be able to calculate the possible earning from the ICO with more accuracy. If the project is in need in the real world then it will be well established then the token will have real value and will be sold rapidly. So after finding a real project you will be able to calculate the cost and earnings from the ICO.