Small talk doesn’t need to be about the weather as the trope goes.

It can be as simple as “hey have you seen {shared colleague} recently?” Or “Hey man, you get into any new hobbies recently?”, or “I’ve been dabbling in {x} tech, have you done anything like it or are could recommend an alternative based on {personal information you got from collaborating with this person}”

The main point in making is that you need to continue in performing these relationship maintaining activities _before_ you need said persons help.

For the extremely oblivious who haven’t researched any game theory but know some comp sci, imagine that relationships with all other humans needed regular mechanical Turk transactions with yourself or they will be identified as high risk groups that shouldn’t be afforded any leeway.