perhaps it is best to establish a decentralized ICO platform which holds investors crypto's which cannot be withdrawn unless certain criteria are met(inverse KYC/proof of project as an example). not only gives security for investors money project developer can do some free/cheap advertising to the platform. sometimes inverse KYC of the ICO raters is not enough I remember Hashcard whom inverse KYC is positive yet it turns out to be a scam.
still...the best way would be a few well known regulator/government/insurance companies that can guarantee the platform as an accredited decentralized platform.