Growing up in a Protestant household, we didn't really do this, but I have at times as an adult. I'm not always successful--the year I tried giving up swearing seemed that I actually swore more during the time. But where I have had success is the things that take time, or rather, too much time. The kind of thing where I think "I should spend less time doing that". And by giving it up for over a month, I've realized just how much time I spend on it and how much better I can use the time.
Just before Lent started I saw something on Facebook by Pope Francis that I printed out. It said Do you want to fast this Lent? It's lengthy so just a couple of things: Fast from hurting words and say kind words. Fast from worries and have trust in God. Fast from pressures and be prayerful. Fast from words and be silent so you can listen... It's helpful to have this out where I can see it. A couple of friends liked having copies of it too. Lent can be a way to start good habits that continue past the season of Lent.