Like any business, you start with a plan.
Its not the most sexy or fun part of the business start up process, but it is by far, the most important. (note: I'm going to assume you've done some market research before you made it this far, and have a good idea that a market for your business exists - if not jump over here.)
Plan & Build from the Bottom Up!
When developing your business plan, do it with the FIND > CLOSE > KEEP system in mind. How will you find customers? How will you close them, and top priority - how will you keep them? Any business that successfully does those 3 things will have some degree of success.
When developing this plan, start from the back and work your way up. Start with KEEP -- because there will be very little point in finding customers, and closing them if you can't KEEP them. KEEPING customers will have a lot to do with solving problems, and providing value. If your business does that, you will KEEP customers.
I should reiterate though, that KEEPING is the most important step, because that is where your highest profit center will be. For the simple but very true reason, that KEEPING a customer is so much easier than FINDING and CLOSING.
The Second Step in Your Plan...
If you've developed a plan for KEEPING customers, and you believe in it, you might think the next step is to run out and start FINDING people to use it. This can lead to a lot of wasted dollars, as you fight your way through the trial and error of how to spend advertising dollars.
Instead, first make a plan of attack. Decide how you will communicate your value, and learn about the triggers that cause people to take action during the sales process. This is arguably the hardest thing to get done right, and it is the thing that will make or break your business.
If you can't CLOSE your business will not survive. But the good news is that even minor increases in the ability to CLOSE lead to exponential results. So spend the time to learn about your customer, what problems they have, and how they talk about them. Then speak their language, and tell them how you can solve the problem for them; faster, better, and with more value (notice I didn't say cheaper) than anyone else.
The Last (Planning) Step...
Okay, so its not really the last step, because once you have a plan, you're going to have to execute that plan, but it is the last step to planning. FINDING customers is when you'll get into the major work, and the work that might change your previous plan. (It's okay if you need to change, being fluid and adaptable is a very good entrepreneurial trait.)
Your business must match your marketing, not the other way around. Marketing should dictate your business operations, because delivering on your marketing messages will be the cornerstone to your successful website startup.
To plan out your marketing, start learning about click through trigger words (which might be different than CLOSING trigger words) and start developing your plan of attack for how to best use your advertising dollars. And this is sooooo important too. Make sure that when you spend money on marketing, that you keep a very close eye on what you're getting in return. (Of course this means long term as well as short term for some businesses.) But the only way, you'll maximize your profit, is by maximizing your dollars on the advertising end. Every dollar you spend should have a visible return on investment here. Maybe building out your business had some start up costs which don't immediately return a profit, but when it comes to marketing, if its not bringing you a profit, it needs to be cut, and be cut quick.
The Real Last Step...
The real last step was touched on a minute ago, but its what all of business really comes down to. There are thousands upon thousands of good business ideas that went nowhere, or took years to go somewhere when it could have taken months. Why? Because of where the "founder" concentrated their efforts. If you concentrate all of your efforts on the idea and how YOU think its so great, you will never reach the success you've strived for. Only when you execute on the reasoning behind your business, when you can communicate why your business is so great, NOT FOR YOU, but for the people you're solving problems for, that is when you'll find the success you've been looking for.
Hope we've helped, and good luck to you! We wish you all of the success in the world!