1. White Paper - if they didn't have take time to create a good White Paper, will they spend enough time to make their product really good? The paper should contain a considered plan and realistic goals.
2. Team - good team, not too big, not too small; experienced. Always check for their background and see if they are active in social media.
3. Growth potential - if the product doesn't have where to grow it will hardly bring you any profit. Make sure to check for competitors as well, because the competitors might have a much better product, even if this ICO growth potential is really good.