Without knowing exactly what your original essay is about, it is very tough to outline out a "great conclusion" for your essay. Conclusions are tough to write. You want to remind your reader about your initial thesis argument and the support that you offered; however, you don't want to be overly repetitive, nor do you want to copy and paste your original thesis into the conclusion. You have to remind your reader without repeating. Another critical component of a solid conclusion is to not bring up new information (this is something that is commonly done by students). Do not bring up new evidence or new arguments in the conclusion. If it is important enough to be in the conclusion, then it should have been discussed in the body of the essay. If it wasn't discussed earlier, leave it out. Finally, a good conclusion should steer the reader into some kind of action or give a final push to agree with the initial thesis argument.