Lower the total actions the account does.
I suspect you use them for scraping?
Also, you probably use DC proxies if these are scraper accounts - the subnet may be flagged by someone's actions.
It may also be the general quality of the account - some accounts get Captcha without doing any actions - you may create the account and it will disappear from search bar after 2-3 days without anyone being logged in. After logging in you'll be greeted by Captcha. If you are dealing with these types of accounts, change creation method/supplier.
You did not really give enough information to give a proper suggestion since I've been guessing what you do with accounts, how they are created and so on. Please add some more info