It is not very easy to identify scams.
Even when the ICO is not a scam, it often becomes a target of phishing attacks: people create fake websites using the project's name (for example 0xproject.info instead of 0xproject.com), use the project Slack to send fake deposit addresses and stuff like that.
Even experienced users should be very cautious.
I can give you some tips that can help you to identify if a project is serious. These are some key points that I and my partners (in the Auctus Project) are considering of extreme importance to show the community our project is for real:
Team: check if the project provides you the real names and information about team members. Check their social network profiles, previous achievements, if you can't find anything about who is behind the project you should be cautious about it.
Bitcoin Talk Forum Thread: See how they respond to critics and doubts about the project here. I have seen some projects that create self-moderated threads (when this is the case, there is a warning message below the thread name) and delete every message that says bad things about their project.
ICO (token sale) terms: See what percentage of the tokens issued will belong to the development team, and most important, see if they defined a vesting period for the dev tokens to be locked. For example, the TenX project had a very successful ICO and they have a 4-year vesting time, so you can see that they are really committed to the project. In the Auctus project, not only the AUC tokens held by the team will be locked, but also the ETH raised. The funds will be released gradually to cover only project expenses.
Product / Development progress: check if the team is actually building something, or if they already have at least a demo or alpha version of their product. This shows they can deliver what they are promising and that they are not only after your money.