If you asked a group of 100 players to list their 5 favorite practices I don't think that 'Long Passing' would show up on the list. The activity itself is not intrinsically fun or exciting. But you can make it challenging and competitive if you turn it into a game.
It's important to first make sure that the players understand the basic technique necessary to pass a ball in the air. Start with the players in pairs, 10 yards apart. One player tries to chip the ball into the hands of another. Once they have some success with this then they move back to 15 yards, then 20, 25 and so on. Starting so close together will encourage them to slide their foot under the ball to lift it.
Next, have the players line up in front of the goal, six yards away. One at a time, the players strike the ball and attempt to hit the back of the net in the air. Those that are successful move back another six yards. This continues until only one player is able to hit the back of the net without the ball bouncing.
The last game is a favorite of my teams. We play a game of 'Crossbar' which I imagine most people have played at one time or another. We play it as a team game where one team has the balls out in front of the goal and the other team is behind the goal. The team with the balls has two minutes to hit the crossbar as many times as they can. The team behind the goal must keep them supplied with balls or the other team receives a point. After two minutes the teams change roles and the team with the most points wins. A progression of this game is to have the players touch the ball forward so that it is moving when they strike it.
An alternate method of scoring is to give one point for every cross that goes over the bar and three points for every one that strikes it. This encourages the players to get the ball into the air.
Games like these can make the most mundane skills fun to work on.
What other activities or games have you used to make long passing engaging and fun? What other ways have you been able to capture the imagination of player successfully with a difficult topic?