On the RF side of Winlink:

HF Nodes:
These nodes often scan two or more bands for traffic. If I'm trying to connect on 80m while the node is busy with traffic on 40m, it seems like I can't connect. In reality, I might be able to connect easily once the node scans back to 80m. 

I find myself relying less and less on the software's Propagation Predictions. I can almost always NVIS my way into the same handful of nodes, regardless of their rating. Most are currently on 80m.

My 80m dipole is at a good NVIS height AGL(.15 wavelengths), so I select nodes within a 300mi radius. However, my 40m is optimized for DX, with a much lower takeoff angle. For connections with it I tend to reach out a bit farther -- between 300-600mi. This is not a hard and fast rule, but it's worth considering your skip zone.

These are just a few things that I've picked up.

Feel free to comment or add your own.

73
Tim
NJ2N