1. Start with the end in mind
My observations are that 'coaches' spend a lot of time in management behaviors rather than coaching - funnily enough my research also shows this, even with good coaches! But one sure fire way to ensure you are not spending all your time picking up and setting out cones and new areas/spaces, is to 'start with the end in mind'. In other words, if you want at some point to play a 3 vs. 3 game or two 3 vs. 3. games, set up your area at the start of practice so that by moving one or two cones you can manipulate the playing area for the different things you want to do in practice. I have also become a fan of different colored cones, or different sizes or shapes of cones, as this helps players, particularly at the younger levels 'see' the different playing spaces easily. I also run around or have a player run around the area we are using for a practice, to help the others see the boundaries. However, the main thing is that starting with the end in mind helps you minimize transition time and 'off-task' behavior.
2. Know the metrics around playing numbers and playing density
There is some pretty darn good research now that shows us how altering player numbers affects the amount of interactions players have with the ball. But playing density maybe has received less attention. We all do it, add a player to an already existing game without making the playing area bigger. Little do we wonder that doing such a thing (which may be purposeful) now means that each player will have less time on the ball as everyone will be closer to each other when playing. Younger players play bunch ball at the best of times, but we as coaches are now adding fuel to the fire!. So please ensure you think of the Goldilocks principle here of not to hot (small space), not too cold (big space), but just right. Here are some metrics from US Soccer to help you. You can think of how this applies to other sports, too.
3. Use pinnies or 'bibs'
Even in my games class I teach at university, rarely do I see coaches use pinnies and I cannot fathom out why? I get that you could make it awkward for players to make them 'work it out' or 'communicate better' but I just can't see how this is productive when your aim is something else. To me, using pinnies is a must. I do not have research to support my assertion here, but if you are doing anything like an invasion game where the court is not dividing the teams like volleyball, then using pinnies just helps everyone out.
4. Keep kids involved and/or make sure they have something to focus their attention
I must be honest, I hate seeing kids 'sat out' when in a physical activity context. For one reason or another, there may be occasions where the players have to rotate in and out, but if a player is rotating in and out it is imperative a coach gives them something 'to do' when rotating in and out. For example, you may assign a player who is sitting out a coaching role, with the aim of giving feedback to the players on their team at the next break in play. You may dig even deeper and have the player on the side do a specific task, like take stats, or pose them two questions, like what they feel the team is doing well and what they need to improve. I have also played a reporter game with players, and this is useful to hear what they are describing going on as they are watching their peers play the game or do an activity. Finally, you may assign them some extra 'skill work' by setting up a dribbling course, say in soccer. Alternatively, if there are two players out (one from each team) you may have them pass and move in a grid in pairs. When they accumulate so many dribbles through the dribbling course or passes then you tell them to sub in. What you choose for them to do may depend, but these are some options that I have used that have been successful for me.
5. Know the three L's and use these to help you plan to avoid them
Finally, I think all coaches, youth sport parents, and administrators do not like to see the three L's of lines, lectures, and laps as these kill the youth sport coach. While I do not like this negative language, youth sport coaches should do everything to avoid these three 'traps'. To avoid lines, use multiple stations or multiple grids or dribbling courses. I know for some things you may need to have a 'line' but make sure you have no more than one or two players waiting in line is a line is a must. For sure and like I witnessed the other day, there is no excuse for having one players dribbling through cones and the other eleven (yes 11) having to wait for a turn!!! For lectures, use a stopwatch to make sure any explanation or interjection in a practice or game is 30 seconds. Using what some people have called a 'show and go' and having this in your mind as a target ensures you do not drone on and the players become distracted. Finally, I never use exercise or 'laps' as a punishment. There are some many proactive steps you can use. One of my players currently keeps 'diving' when being tacked in soccer, so I ignore it, and he his diving is beginning to become less and less as he knows I am not reacting to it. Sending the player on laps is not worth damaging the relationship I have built with that player.
In conclusion, I hope this is useful. Please leave me some feedback or ask any questions.