Courses taken in English and in mathematics that are preparatory usually are non-transferable. According to USA Education Guides, the most common non-transferable courses are "English courses, which prepare the student for college writing but are not English Composition I" and "elementary or intermediate algebra" since "college algebra is the first such course offered for degree credit at the vast majority of universities."
Many two year junior colleges and community colleges have explicit agreements with nearby four-year institutions about what credits will transfer. The community or junior colleges, or "feeder" schools, have agreements with these "target" schools. College Transfer.net suggests that students "check out the agreements with possible target schools" and offers a service to investigate what courses will transfer between institutions.
Credits can expire. For example, Xavier University states "credit over ten years old will not be accepted if the course in question belongs to the student's major." They will, however, accept credits over ten years old if the class is an elective. Credits often must match up with courses at the new college. For instance, UCLA's website states that students planning on transferring credit, "take academic courses which are substantially similar to those offered by the University of California system."
Xavier University's website states credit is given for courses "in which a grade of "C" or better has been received." The credit must come from an "institution that holds regional accreditation with one of the following institutional accrediting bodies..." The list includes accrediting bodies such as the "NCA - North Central Association of Colleges & Schools." Get good grades, attend a feeder school, and transfer within the specified time to keep credits.