Too many players get to a field and the first thing they do is start shooting on goal.  They do this without warming up properly and in doing this, put themselves at unnecessary risk of injury.  Here are some activities that are an excellent way to get them warmed up better for passing or shooting and take very little time.

Here is a simple warm up activity that works on passing with accuracy and proper pace over the various distances

Groups of 2's with one ball per group.  The players start 5 yards apart and pass one touch 5 times (successfully) with their right foots only.  Then they switch to five passes left foot only.  See diagram for a basic set up for a group of 10 players

Once they have been successful with 5 passes with each foot, each player moves back 5 yards so instead of being 5 yards apart they are now 15.  They do the exact same thing with 5 consecutive passes with the right foot and then 5 with the left foot.

Next they go back 5 more yards each and do the same thing from 25 yards apart.  This time, in order to encourage them to start driving the balls instead of just using the inside of the foot, they can play two touch and really strike the ball hard

After 5 passes with each foot from 25 yards apart, they go 5 more yards back and can now either drive the ball or chip the ball to each other.  Again, it's important that they use each foot before progressing.

If you do this simple progression following a run and stretch warm up progression, the players will be prepared to do whatever you want in your training session.  This only takes a few minutes of time and will help prevent unnecessary injuries due to improper warm up.  Think about how much better an easy routine like this would be for players when they first get to the field as opposed to what players normally do which is start right off by shooting on goal as hard as they can from the 18 with absolutely no warm up or stretch.