Even a thousand-mile journey begins with the first step
Start (functional) coding from the unit tests.
In case if UI, move the code to the view model.
In case of (WCF) WS, write a simple (cmd/console) consumer.
In case of dependency injection IoC containers, implement a stub or a mock up.
In case of SQL, use a light ORM and switch the db context to a predefined set of entities.
The very first step is always the high level design. You don’t need a IDE… but a piece of paper 😉