If you have a lot of players on your roster, it can be a nightmare to organize who is going in when. In addition, you can be constantly interrupted with questions about "when do I do in, coach?", which will distract your attention from the game. With all of these distractions, you can forget to put a player in - or lose track of the time to sub. This is a sure-fire way to get lots of players and parents upset with you.
What works? One of the easiest ways to handle subs is to get a dry-erase board (about $10 at your local Walmart or equivalent) and a wind-up kitchen timer.
Put all of your positions (G, SW, RD, CD, etc.) on the board, in the formation that you intend to use. Then, divide the game into sub-in periods. Your league automatically may divide the game into quarters - and only allow subs at quarters (except for injury). As players get older, subs usually can be made during throw-ins in your favor, or on goal kicks or kickoffs.
For teams that are playing 11v11, it works well to divide the game into 6 sub-in periods (players may tend to call them "quarters" anyway, so you may have 6 "quarters"). This means that you have 66 available time slots. Divide this by the number of players on your roster, and you will find out the number of periods that each player can play (assuming equal playing time). With 18 on your roster, you would end up with everyone playing 3 time slots - and 12 players getting to play 4 (18x3=54 +12 = 66). You know that, at any given time, you will need to have 7 folks sitting out, right?
Next, put the names of the players - and the period in which they will be playing - by each position shown on the board. Then, at the bottom, put down who is out for each (this acts as a check on your positioning - as you will be over/short if you have somebody in 2 spots at once, etc.). Generally, you will want to have your strongest players in at the start and end of each half, so this likely will play a large factor in your list of ins-outs.
The list of "ins/outs" serves as a good balance to double-check that you don't have one player in two slots at the same time. It also serves as a good check to make sure that you have not shorted anyone on intended playing time. Even players as young as U-9s can be trained to use this system. It has lots of benefits, as they can see at a glance that others have to sit out (or get rotated into positions which they don't always like). In addition, because they know where they will be playing next, they can get warmed up and ready to play - and can watch the area where they will be playing to size up the opposition.
If you have unlimited subs, you will need to set your wind-up timer for about 1 minute less than full time for the quarter (to allow for problems in getting subs in), then put the timer on the bench where the players can see it. With 7 on the bench, somebody is going to be telling you/them when it is 2 minutes or so until time - and getting everyone ready. The list of "ins/outs" makes it easy to call off your players who are subbing out - and to count noses to see if you have 7 on the bench.
You will want to adopt a rule to get a player who is replacing somebody who is staying on the field - but moving to a new slot - to remember to look for where that guy is going so that he can tell him when he replaces him. In addition, you will want to try to always have a reasonably good player on the bench during any sub-in period (so that you can make a rapid substitution in a critical slot if you have an injury). This list of available players can prove to be very handy, as players have been known to awaken at 7:00 a.m. with a high fever when your team has an 8:00 a.m. game - and it becomes pretty easy to change the board at the last minute by dividing up the available extra slots among those in the "bench pool".
Many coaches put their lineups on regular notebook paper and keep them in a 3-ring binder - and this can prove to be a useful resource for times when the coach has some personal crisis, and needs to grab a quick line-up at the last minute. It also can be useful to go back and look at lineups which worked, and those which didn't, to see which players seem to work best together and to spot areas where a particular player may need more development. Even if you choose not to publicize your lineup in advance, for fear of hurting feelings if you need to make mid-game adjustments, this method of filling slots is still useful - and the windup timer is lots easier to set (and keep track of) than a watch.Updated 1 April 1999