If you've taken a marketing class, you were definitely taught about the "4 P's" (Product, Place, Promotion and Price). I could sit here and talk about that, but I'd rather get a little more specific and talk about how it pertains to internet marketing.
What are you selling? What are you offering? What makes you unique compared to your competitors? These are all very valuable questions to ask yourself before moving forward with an advertising campaign. Perhaps you have many products that you offer. You must decide which product will be most effective to advertise. After all, you're going to be spending money on a campaign, so it would be valuable to show off your best product or promote a new, highly anticipated one.
Marketing is much different online than it is conventionally (TV spots, radio, magazines, etc...). You have to remember that it's a lot easier to avoid an advertisement online than it is when you're viewing other vehicles. It's imperative to have your best foot is forward to attract the visitors to your advertisement. You really have about 2 seconds to attract their interest, or they're going to view the content they're searching for. You must use this time wisely and present your product in such a way that it is attractive.
I've seen really great products being advertised poorly. The creative is really important to get right. It should definitely blend in with the site and at the same time make the product relevant and present. Keep this in mind when you're launching a campaign for your company.
Placement is the MOST IMPORTANT DECISION you can possibly make. It's really important to find the best places to put your ad. If you're advertising SEO optimization, it would be really unwise to put that advertisement on ESPN.com (unless you're behavior targeting) . Most people, and by most, probably 99% won't even care about SEO optimization. It would be much better to place that ad on a site that has a SEO portal. Regardless, I've stressed this in other posts: Target your audince wisely. If you can target within a website to specific sections to optimize your targetting, then do it! You want to always hit your niche market fully forward. It's like watching a makeup commercial if you're a guy. You're really not going to care about it. Advertisers waste millions because they're not targetting well enough.
Placement, for all you old school marketers is generally your location. Since we're in cyberspace, the best location is the first page on Google Search, preferably one of the top 3 links.
Pretty self explanatory stuff here. Whatever you feel your product is valued, then you should charge that amount. Of course, this comes with a matter of reasonability to it. Charging 50% more than what the product is worth is not fair to the consumer and will not be attractive. Usually when you want to advertise a product, you want to include incentives. Generally, incentives are what win people over. The best campaigns give value to the purchase. "Save 15% off by clicking this link," generally attract people. It's a marketing rule of thumb. Make people believe they're getting value and they will tend to buy things more often than if there were no incentives.
This will tie more closely in with brand awareness than anything. Since you need to promote yourself regardless, you should always consider brand awareness. Sometimes you feel like a campaign costs too much because you're not getting a high enough click through ratio. That's okay! People still saw your brand. Believe it or not, a little protein molecule in their head has formed with your brand! Whether they'll remember it or not is completely up to how that molecule was formed (Science rules). Get out there! Go to trade shows, conferences, after parties, networking events, conventions, etc... IF YOU NEVER EXPOSE YOURSELF, YOU WILL NOT SUCCEED!