Affiliate Marketing Secrets

i was wondering, what happens when a customer visits the vendors page through my hoplink, waits for somedays and confirms if he should buy the product. And re-visits the vendors page directly without going through my hoplink (obviously, by now he knows the url of the vendors page of the product he’s interested in) and makes the payment, will i still get my comission? If not, then is there a way to avoid this from happening?

I have been an affiliate for a year but making very few sales. How can I make good commissions? Please help!