You can invest in ICO's, just watch out for the following (non-exhaustive)
- Do they mention future profits on the website ? (buy now, profit$$ later) => most likely a scam
- Look at the team, look at the linkedin profiles. Do they seem competent? Do they have legit work experience? Does that experience add value to the project?
- Is the team sufficient? If their poject is world changing and there are three people on the team, probably a scam
- Does it offer a solution to an actual problem? Or does it at least add some value? That alone will eliminate a lot of ICOs

Hope this helps,

Cheers !