The strategy, as I see it, is pretty simple. Accumulate as many trade assets (including 1st round draft picks) as possible.
Play the young players and give them a chance to show their abilities, try to build up their trade value. This means giving minutes to Avery Bradley, not signing Monta Ellis even if Ellis would make us marginally better in the short-term.
Have the ability to execute a big trade in the future - meaning either cap space (unlikely), traded-player exemptions, or expiring contracts.
Basically, be ready and able to take advantages of opportunities when they present themselves. TRADE opportunities; Danny's a trader at heart, and free agency is always tough. Free agency means overpaying for your guys, when he'd rather be able to acquire a player via trade at a discount. He had the valuable young assets/draft picks to grab Ray Allen, and to take advantage of KG's finally wanting to be OUT of 'Sota, and the expiring contracts to make a deal work logistically.
Antoine called Danny a "snake," and that's kind of how I think of him; waiting in the weeds for a big opportunity to present itself. In the meantime, accumulate as many trade chips as possible.