Instead of DIY, are you really referring to project managing the different parties who will be working on your flat? I just completed mine - it was very tiring but you gain satisfaction from the fact that you know almost every detail of what went into your house, not to also mention the monetary savings. To start off, you need to have a clear idea of what you want to achieve in your flat and then source for different parties to work on it. For example, getting reno permit with proposed hacking, engaging hackers to remove old built-ins/tiles/etc, mason, carpentry, electrical, plumbing, ceiling, painter.