Execute well, there is not much else you can do. Execute well and milk it as much as you can if competition comes in you can change your pricing, structure etc. to crush them if you like. But in many sectors you won't need to beat your competitor badly anyway, you all can live happily.
You need an "unfair advantage" See Jason Cohen's posts about it here - http://bit.ly/b7IrVR - and here - http://read.bi/aUNNN9 For what it's worth, execution is not just about technology. It can be about soft skills too. You can have an unfair advantage because you give up some margin to have the best customer service, etc.
Nordstroms instead of Walmart. Google instead of Alta Vista, Excite, etc.
Be first to market in a big way. Do a media blitz and social networking blitz which is very well orchistrated to get the word out. If it is easily "copyable" the best solution is to be known first.
I don't think pure execution will cut it in the long term (and probably not in the short term.) Remember that the players already in the market have had a lot of experience now in how to make their businesses work.
You need to create a sustainable competitive advantage. If you can't do this, you need to seriously question whether the idea is worth executing and whether someone else can easily execute too and cut you out of the market. Here are some strategies you can build into your business model to make it difficult for other people to set up in competition to you.
Capture your market fast Create a large market share quickly so competitors will find it difficult to get customers. This works especially well when your product or service has network effects. However, it is not quite so easy to achieve as it sounds!
Create a brand Brand loyalty and reputation will help customers stick with you rather than switch to a competitor.
The iPhone is a classic example. There are more functional phones on the market but customers buy iPhones because of the Apple brand, image and reputation.
Register patents, trademarks or Intellectual property protection All these things can be protection for your business, but only if you have the money to defend them in court. The other disadvantage of patents is that you have to spell out the details of your invention which are then accessible to everyone.
Have a trade secret If you create a product, you can keep the ingredients (or some of them) secret. Think 11 secret herbs and spices or Coca Cola. You can do the same thing with business processes. Sometimes this is a better way to go than patents.
Create exclusivity with suppliers Having an exclusive license to sell your suppliers product means that no one else can directly compete with you.
Create exclusivity with distributors Have an agreement with retailers/wholesalers so they can’t sell any products that compete with yours. For example, most vending machines only sell drinks from one beverage manufacturer.
Government regulation If you can get the government to pass legislation that mandates the use of your product/service, that is a huge advantage.
Access to scarce resources You may have access to resources that others do not.
Foe example, mining leases give materials companies the right to sole access to mineral deposits. Businesses that are a monopoly often have the same advantage.
Having technical or other staff with specialist know how that is rare may be a barrier to your competitors – as long as you make it worthwhile for them to stay with you.
The ability to borrow funds when others in your industry cannot can effectively stop others from entering. Access to a particular location or key contacts are other examples.
Having ideas is easy, good ideas are harder. But no one buys ideas, they buy solutions to their problems. You have to make a complete, easy-to-use, easy-to-buy solution out of your idea.
Remember, anyone (including you) can flip burgers but McDonalds made a global enterprise by doing it the best
Think of a critical service you can tag on to your product that requires special relationships (with a celeb, a larger company in a different sector, etc.) which are difficult to reproduce. This can very well be low-tech and require on-the-ground work.
I think this blog post by Mark Peter Davis, a fairly successful entrepreneur-turned-VC-turned-entrepreneur, is worth reading while you're pondering the subject. I don't necessarily think his thesis is a complete picture of what makes companies successful, but these are three good starting points, covering the ways that most of the startups that have "made it big" in the last ten years did so.
Also worth noting that all three of his categories are very similar in a way. You have companies which do well due to network effects, like Facebook / eBay (if you're going to use a social network / online auction site, there's a strong benefit to using the largest one); you have companies which do well due to prestige effects, like Google (if you're a smart person and you want to build cool technology, there's a strong benefit to working where you think all the other smart people work); and you have companies which do well due to other prestige effects, like Microsoft (if you're a corporation trying not to disadvantage yourself with respect to your competition, there's a strong benefit to using the same products they're using). If I had to rank the three, I'd rank them in that order - there's really no disadvantage to the consumer in the first scenario, there are arguable disadvantages to the employee in the second scenario, and there are definite disadvantages to the corporation in the third scenario (avoiding a risk also takes away an opportunity).