A college interview should be a conversation, not one-sided. If you feel like the interviewer has heard enough about your strengths and is ready to move on to another topic, stop talking about them.
Look, get a sense, then use your gut
You can also use body language cues from the interviewer as an indicator that it's time for a new subject; if they appear bored or uninterested in what you're saying, then there's probably no need to keep going down this path of discussion any longer.
Probe, and if the interviewer is interested, he'll voluntarily ask for more.
Additionally, try asking questions related to yourself and see how much detail they expect in response - if their replies are short or don't require elaboration on your part then maybe it’s time for something else!
Or you could just ask.
If all else fails, simply ask the interviewer directly: "Would you like me tell you more about my strengths?"
This way at least gives them an opportunity express whether or not they want hear additional information from your end before continuing with other topics during the interview session.
If they say no, then talk about something else.
If they say yes, then continue talking - but make sure you are succint and not repeating earlier points.
Draft an outline of your talking points before the interview; this helps you keep to topic without being overly lengthy
It may help prepare beforehand by writing out key points that highlight why those skills make up who you currently are so when asked (or even anticipate being asked), you know exactly which points will best represent yourself within reason without overdoing it too much.
An outline can be simple bullet points you draft out when you prepare for the interview. It doesn't have to be very detailed or elaborate. Just stuff you know you want to say and can help you create conversation during the meeting.
You don't need to talk about ALL your strengths. Just mention the key ones.
Lastly, remember that although these interviews focus heavily upon individual qualifications/experiences etc.,it doesn't necessarily mean every single strength needs addressing.
Assess each question carefully & only discuss relevant examples depending on its context thus preventing unnecessary talk altogether.