There are many career option for average students. You may be average while studying but You excel at work. All career option can an average student pursue except few like academic research which requires a lot of knowledge in respective fields.

There are many govt jobs you can find for which you can apply to depend upon your skills, If you try and qualify then its good if not switch to next. In the private sector, You have many chances like if you have good communication skills you can go for Media or Acting. 

If you have the good convincing skill then you can go for sales and Marketing related jobs in the Private sector. If you know programming then You can be a software developer. If you are good at design then You can be a Graphic designer.

You have a lot of career opportunity in the Private sector but You should be an expert in something In short if you have some skill then You will be able to get jobs without being a topper.