And why do you think that your glider should perform better? Perhaps you've got the best performance. Do you know what is the best? Do you know how to classify the performance you've got? Once you've answered those questions you'll be able to determine what if anything you can make better.
For example, from the information you've supplied you should be able to estimate lift/drag ratio. And if you compare that with anything from Space Shuttle to 747 to high performance sailplane you'll get some idea of how indifferent your design is. Of course with such low Reynolds number flows you won't necessarily be able to compare like with like, but it's a start.
Engineers communicate using the written word, supported by mathematics. That's why punctuation, spelling and grammar are all important. That's why your course looks for an English qualification alongside the Maths and Physics. And that's why in your forthcoming degree examinations the script books have instructions to candidates which, inter alia, state that 'Marks may be deducted for.....' I guess pprune's as good a place as any to practise getting it right.
Good luck
