What is the most effective approach to conducting KYC for an ICO?

There are plenty of providers that can provide KYC services and liveliness tests that are essential for any kind of online offering, including an ICO.

However, be cognizant that not everyone has a passport, so if the passport is the only acceptable document for online verification, then be prepared to lose out on a large swath of the population who would not be able to qualify.

Secondly, also make sure you understand the primary and secondary ID of each country that you intend to sign-up for. Ask your solution providers if they can process such identity documents for online verification.

Some of the famous names in the game are ShuftiPro, Jumio, IDology, Onfido, Trulioo, IDNot, GetID, etc.