Preparing for Lent in advance of your pilgrimage is a beautiful idea! In regards to practices, I recommend starting with the 'why' question. Assuming you are unfamiliar with the purposes and practices of the Lenten season, doing a little Googling. While I cannot speak to other religions or faith traditions, here's my take from a Catholic sinner's perspective.
Prayer is an incredibly important Lenten practice among the faithful. When walking the Camino, you've got the time for a conversation with God. A Rosary a day is easily do-able. If that's too much to start, consider just doing a decade of the rosary here and there each day and, perhaps, build up from there. Attend Mass whenever you can and (if you are Catholic) take the sacraments, even on weekdays (side note: taking confession before starting the Camino really works for me; consider it if you're a practicing or fallen away Catholic). Maybe make a commitment to doing the Stations of the Cross once a week (Fridays during Lent are a popular time for that).
The fasting and abstinence parts are important Lenten practices for Catholics. When speaking of abstinence in reference to Lent, that means regulating the quality of the food we eat (aesthetically, not necessarily nutritionally). So maybe take a pass on the café con leche or sticking to the pilgrims menu and drinking more water and less vino tinto. I think that abstaining from meat on Fridays during Lent is easily done on the Camino, but consider whether you need to strictly fast when what you really need are the calories and nutrition to keep on walking.
Lent is also a penitential season in which we strive to atone for our sins and purify our lives in preparation for the Easter celebration. 'Giving something up" as a form of penance is a common practice. Consider that you will have already given up the comfort and security of home, and probably at no inconsiderable cost to do so. Unless you are taking the bus from village to village every day and enjoying a sumptuous banquet every night, you are certainly already practicing a form of daily penance (some would say self-mortification), so offer up those sore calves, achy back, and blisters. If there's something else you are moved to sacrifice, then go for it but there's no need to make yourself (and certainly not your companions) completely miserable.
A final Lenten practice is to keep the spirit of almsgiving. It can/should be more than leaving money in the poor box (which is still a great thing). Think "selflessness." Be that person who provides for another pilgrim when the opportunity inevitably presents itself (it will, every day). Be that generous pilgrim at the donativo. Thank a nun, a hospitalero, or a shopkeeper for her devout service.
God bless and buen Camino!