promotional activity would depend on the kind of business you are promoting on the internet.
If you are looking for branding you'd promote it with cost per million basis
If you're looking for sales, you'd go for affiliate marketing
You'd go for CPA if you are looking for leads.
If its an information product and you want more visitors you may go in for cpc.
Promotion tactics you could use are to give away a free ebook or something of value to the person visiting your online business.
Explain more about your business and you'd get relevant ideas.