The method to finding a good internet marketing strategy is going to completely depend upon the type of business that you're trying to start or promote. There would be a big difference if you are trying to sell women's clothing or if you're trying to sell auto parts. There would also be a big difference if you're trying to promote your own product or if you're trying to promote some elses product or service. The reason for that is because if you're promoting your own product you would have 100% of the money from the sales to work with, therefore a higher advertising budget than you would if you were only receiving a commission from each transaction.
Affiliate marketing is one area where this is common. You may have both affiliates and merchants bidding on the same keyword phrases using click advertising. In most cases the merchant is going to win this battle hands down simply because they are getting 100% of the money from each sale and have a higher advertising budget. Some smart affiliates will be able to compete by using different internet marketing strategies, however, that's a story for another time because each situation is different.
The best internet marketing strategy that you could use if you're just starting out is to test and track everything that you do. This is something that you'll want to do over the long term for everything that you do online. By testing and tracking everything you'll know exactly where your money is being spent, where your leads are coming from and where your profits are being made. That is the best internet marketing strategy you could ever use.