I am not an expert, but I've been around this block a few times. Be VERY careful about the wording of your friend's invitation letter. Coming to see your girlfriend in Canada may appear to them as a TIE to CANADA which could overwhelm other ties to your country. Anything your father has done will not be of much value to prove YOUR ties to the country. And, if your Dad is comfortably off, showing that your tuition fees have been paid for two years is not that significant, so it may be best not to mention your Dad's situation. Do you see where I am going here? Almost anything you can think of that feels like a positive tie to you can be viewed the other way around by the VO and frequently is. That is why I suggest you read everything you can about the rejections so you avoid the traps. It IS extremely sad and frustrating when you know in your heart that you will return to write your exams (that is a good one to include), yet there is no way to know if they will accept or reject your request. Is there anyway you can tie in your trip with your studies??? I don't know what subject you are taking, but would it be likely that you could futher your education in Canada, are there specialized courses in your field here that would not be offered in your country, or something like that? Could this trip be a chance to check out Canadian institutions. I don't know the merits of this, but see what others think?