I've had experience with both test stripes and liquid tests and I agree with everyone thus far - get an API test kit if possible....so well worth the money! If you have a fish-in cycle, I would personally do about 25%-30% water changes every two days, unless there is a spike in ammonia or nitrite...then I would do more frequent water changes (i.e. every day until the spike goes down). Once you have good 0 readings for both ammonia and nitrite, and some readings for nitrate (I waited for five days straight to get these readings - but that's just me!), then I would slowly add fish (about 2-4 per week - depending on size and current stock). Testing can be annoying - but it is well worth it as these little finned babies' lives are in our hands!!
PS - do you know anyone who has an established, healthy tank? If you could score some of the media from their filter that would help the fish and the cycle move along! I don't think it wold be too late to do this, if it is possible