Only need tickets for the night practices. They're free, but you have to get them in advance. That information, as with the yearly shuttle-parking changes, probably won't be available for at least another couple of months.
All morning and afternoon practices are free and open to the public, with the possible exception of a scheduled VIP day (normally on a Sunday), the walkthroughs before preseason games, or inclement weather. You'll still have to park offsite and catch a shuttle to St. John Fisher, though, unless you know someone who lives within walking distance of the campus.
This team normally doesn't run many two-a-days, and virtually none after the first week of camp (which will be the last week of July), so the first couple of weeks will give you the most potential practice dates to choose from. Try to catch an evening session -- nice to see them on the turf field, under the lights.