Well it depends partially on what denomination you are in.
Roman Catholics have specific requirements about fasting during Lent. So if you practice Lent in the Roman Catholic manner they pretty much tell you what you need to do. Although you can always add in more.
I believe Eastern Orthodox churchs also have similar requirements.
Lutherans are more Laize Faire on Lent. The idea behind it is to simplify your life, devote extra time to God, and to understand sacrifice.
From there you choose what you will do to observe Lent. Typically I do two bible studies during Lent and give up something. This year I'm giving up sweets like candy, cake, ice cream etc. (Deserts) Although I'm only doing one bible study this year because of my upcomming wedding.
I will say I don't particularly like Lent, and I only observe it because I think its good for me to do so.
One of the biggest things I dislike about Lent is that in church, all joyful hymns are taken out of the service. Alleuah is a banned between Ash Wednesday and Easter. And its rare to find a Lutheran pastor who will do a wedding during Lent. That is why Melissa and I's wedding date of April 10, (First Saturday after Easter) is not an accident.