First of all you'll have to accept that there is no guaranteed way to ensure that good performance leads to a graduate offer.
However there are a few things or tips that might help you to make a good impression.
1) Be a good listener.
2) Don't be a yes man. Learn to debate in a way that doesn't offend senior management and at the same time doesn't lead to situation where you get overworked.
3) Start slow and build up. A lot of times, we expend a lot of energy in the beginning of a job or internship which simply isn't maintainable. This leads the management to think that your performance is getting worse. On the contrary, if you slowly improve and work smart, it'll give the impression that you continuously are improving.
4) When disagreeing with your seniors use 'and' instead of 'but' when countering their opinions and build on that.
5) Be punctual.
6) Make sure that the boss of your boss knows what tasks you've performed for your boss. Otherwise in the eyes of upper management, your immediate boss will most likely take the credit for it.
7) Learn to handle criticism.
8) Work Smart.
9) Hope for the best.
Good luck to you mate