i pay attention to other peoples teams as much, if not more than my own team. knowing what who you will be bidding against, how much money they have compaired to you, and what their spending habits are like are huge parts of it. if i know someone well enough to know that they value someone super high, ill push the price up on a player even if i dont want them. worst comes to worst you get the player and trade it to them anyway. but the less money in other peoples pockets, the better. its a risky stratagy but its too fun to not do.
those are the 2 things i do consistently. i watch what other people need ( this also lets me know if i should put someone out there to be bid on that someone esle might want that has a position of need that said player fills, giving me a better chance of when the player i DO want comes around, ill have one less person bidding on them ) and i make sure to push bids up when i can. you dont want people getting players for free. you dont always have to do it, but do it when you can or are confident that they will go higher.