Establish whether there is a real user need to have a set of terms and conditions. If there is no need, then don't do them.
Write the terms and conditions in plain language, or translate them to plain language
Publish the full terms and conditions on your site. Do not require log-in access. Make the terms and conditions page available at a consistent URL between servces, for example /terms-and-conditions.
Make it clear when terms change, including making all previous versions of terms and conditions available online with data about when they were applicable.
If the terms depart from what could reasonably be expected from a digital service, then make sure that they are explicitly stated within the transaction - ideally from the part of the transaction that relates to those terms.