A first order rule-of-thumb is that IP3 is roughly 10dB above the compression point, or P1dB. I'm assuming you understand the definition of what IP3 is and what it means, and its relevance. If you don't, just let us know and we'll clear it up for you.
Therefore design the amplifier to have a compression point roughly 10dB below the IP3 target.
There are additional tricks you can use to further improve the IP3. These tricks generaly are narrow band in nature, may not track well over process, and may be difficult to apply. However, they are worth looking at. Here's a document I wrote that explains these tricks:
**broken link removed**
Greg