I should never, ever allow myself to get into the frame of mind of persistently trying to dance with specific people at a festival - or even at an ordinary milonga. All it does, is make me distracted and indecisive, so that I miss out on other opportunities.
Thinking like that can work for you if you have the right kind of focus, but it totally distracts me and takes me out of the moment.
The only way to plan ahead that works is agreeing with a friend in advance that we want to dance something specific that we know is coming. I don't like it when I feel someone is chasing me, even when I would happily have danced with them otherwise, so it makes no sense to do it myself. And they know perfectly well where I am, and will come and get me. I should always look around open-minded for the tanda.
At large festivals - more than 200 people - I'm not in danger of making this mistake because I can't keep track of where people are that precisely anyway.