I keep a close watch on different ICOs and try to buy them when they are not yet listed on trading sites so I buy them at very cheaper rates and sell when I see higher price on sites once they are listed as its the most easy way to make profits.
But investing in ico also involves a huge risk as I have seen in the past that when coins get listed on sites they simply disappear in a single day and only the owners make profits from that and majority of investors are sitting on loosing end.