Why you failed might help with suggestions too, lack of ability is quite different to lack of effort or extenuating circumstances such as illness.
If you had problems then why? Did you fail narrowly or widely?
What was your rationale behind going to uni, was it a requisite for a career path you want to follow or more of a something of a progression from college etc...
Did you enjoy the subject and the course?
A little more context would be useful, what you were doing, why you failed, what you wanted from uni, what you want to end up doing etc...