Well, the summer is over and unfortunately that's where you could have done the biggest improvement. However, here are some things you could do:
- start reaching out to alumni currently working at banks and ask for a quick phone call. keep the message short & sweet and don't go the carpet bombing method (make sure you tailor each message to the person you are writing to)
- try to get some higher position at a society: other than simply being a member. Ask for some legit responsibility if you can
- are you good at something? you could try freelancing at sites such as ODesk.com or Elance.com, however, this one will take a lot of your time (all the prep and the work combined); but will definitely boost your profile and you can also earn some money
- try some activities and see if there is one which you really enjoy. get on a hobby which you really like.
- and finally feel free to upload your CV to the shredder, it does matter a lot how you present yourself/your background