Hard to avoid, here is some tips.

3 Ways to Identify an ICO Scam:
1. The Developers Are Anonymous
The first and most blatant sign of an ICO scam is that the token’s developers are anonymous or otherwise-unknown.
2. The Token Does Not Have a Clear Use Case
Another sign of an ICO scam is that the developers are unable to clearly articulate a valid use case for the token.
3. The Whitepaper Sets Unrealistic Goals
If the whitepaper sets an unrealistic development schedule, it either means the developers are using deceptive tactics to attract token buyers or they lack the necessary experience to give a sensible scope to the project. Either way, this does not bode well for the success of the project and its corresponding token.

99,9% ICO's are scam's
How to know its real deal?
1. The Developers Are Anonymous
2. The Token Does Not Have a Clear Use Case
3. The Whitepaper Sets Unrealistic Goals
Don't waste ur time in ICO's

#1: Does the use case make sense? Who does this coin solve a problem for? (besides the people selling it!)
#2: Have they made any concrete progress on their roadmap?  Is there code on github?
#3: Is it closed source?  If so, the odds of it being a scam are much higher unless they have a really good reason.

What i've noticed is fakers are usually using ready made sites. If their site is built on a common, free template, and you can see it doesn't have a lot of features and nobody paid for making it, you can smell a scam. A legit dev team won't be afraid to invest their money into the project.
Next thing I usually notice is the fake pictures. If the pictures of their team members were taken from other sites you can expect a scam as well. If you are planning to put fake pictures, it's better not to include them at all.
Any fake info should disqualify the project, like a fake address, fake picture of an office or the office building, company registered at a common address used by many other businesses, where they're just renting a room to be able to post a location. Check everything.

I is difficult to say for sure, but there are some things you should take into considerations: often projects which already have some products are more trustworthy, besides project should have reliable team, it should be active in social media, but not just posting, but you should assess the quality of the content.

Check their Team member.There should be Social Media Presence like Telegram, Discord, Twitter and Facebook And It should be active.The Whitepaper Sets Unrealistic Goals. i personally prefer ICO CVproof is best .because of its team and project .

1. I would advise you to check the photos of the founders through Google search, sometimes there are absolutely other people in these photos.
2. Look at the ratings on sites like icorating, there part of the work on analysis is done up to you. Not necessarily the rating should be 5 \ 5, but if it is too low, it should alert.
3. I assess the essence of the project - how much it is needed in the market and  would I invest in this project as an investor.

Read whitepaper , a big group member, profession website, partner, member of ico,...

check if they have a prototype

if it's a lending platform promising unrealistic returns, that's a scam. also, be wary of airdrops asking for KYC before they give your free tokens. for me this is a red flag.