I regularly check the "News Center" to see whats happening with other airlines or cities.
One important piece of information if you can make use of is when an airline goes bankrupt or is liquidated. This information instantly tells me that there would few slots that have now become free. However, the news that gets displayed only tells the enterprise name and does not give out the country name.
If I know of an enterpise that has got liquidated for instance in United Kingdom, that would tell me that slots at Heathrow have become available and I can try and fit my flights in there.
Thoughts???