Students actually getting into groups is essentially wasted time (unless it is one of the few types of activities where you can get them practising particular language at the same time, e.g. by combining it with a mingle stage or get them to form their own groups by particular criteria), so the quicker the better. Things to think about if you want to speed things up include minimal movement of furniture and people, and a way of grouping people that can be quickly explained and quickly and easily understood. Students deciding on their own groups can cut down on explanation time but waste time while they decide who to work with, so you might want to think carefully about whether the students particularly need training in taking responsibility for forming groups or not.
2. Minimal noise and distraction
This is especially true if it could disturb the class next door. This means both the noise from getting into groups (less moving of furniture and people and people knowing exactly where they should go equals less noise), and noise from the actual groupwork (smaller groups of people sitting closer to each other and not needing to talk over other groups equals less noise).
3. Right amount of moving around
In certain situations a bit of lively noise and stretching your legs and other muscles as you move yourself and the furniture might be just what students need to wake themselves up and provide a bit of mental rest before the next classroom task. If so, quickly moving into groups like this and then doing a fun sit down game can be just as good as doing a stand up warmer/ filler. Otherwise, minimal movement of people, furniture and belongings such as notebooks is usually best.
4. Pair up the right people
Take into account: language level (do you want to pair people up with someone similar language skills or do you want one higher level person in each group/ team?), personality (will they get on and does each group have one natural leader in it?), world and other knowledge that at least one person in each group might need, class history (have particular people clashed before or do they work together too often, or has one person missed a recent class or joined the class recently?), and cultural issues (e.g. men and women working together, age and seniority issues).
5. Suitably random
If students get the idea that you are choosing certain people to work together all the time they might come to their own conclusions about what assumptions you are making about each person and there is the chance of people being offended or being forced into a particular classroom role. You might therefore want to also use random groups or at least create the appearance of randomness.
6. Suits the classroom set up
For example, getting into groups the way you have planned does not depend on false assumptions about the amount of space available or how easy it is to move the furniture in that room, making sure people aren’t put into places from which it is difficult or impossible to see the board etc (also taking account of reflection from lights and windows), avoiding hot and cold spots (right under the aircon, by the draught from the window, in the sunlight not blocked by the blind), etc.
7. Allows them to use the materials they have been given
For example, if you move them all away from their tables they might have nothing to balance the photocopies, board or playing cards you have given them on. Also, if they are too close together they might be reduced to throwing the beach ball to the same person each time or just passing it to each other.
8. Don’t distract the other groups
One way to ensure this is to start one group on the first discussion question and ask them to work their way down the worksheet while getting the neighbouring group to work their way up from the last question. If some groups will be doing the same thing at the same time, sit them as far apart from each other as you can.
9. Can monitor all groups equally easily
This usually means leaving room round the back of their chairs so you can get all round the classroom and stand in an unobserved position behind them to listen for errors, students doing the activity wrong etc.
10. Think about whether the teacher should take part or not
Taking part in one of the groups means you can continue the game or discussion you started when demonstrating it with another student for the whole class, that you can make a convenient number to split people into equally sized groups, that you can correct a bad group dynamic (e.g. one person dominating), that you can pair yourself up with someone no one wants to work with or who thinks they are too good to work with the other students, and that you can provide lots of error correction for particular students who insist on having more. The main disadvantage is that it is very difficult to monitor the other groups, but there could be other problems such as the teacher being in a group changing the dynamics of the groupwork in a negative way. For example, having the teacher in their groups could make them concentrate too much on accuracy and therefore not free their speaking up enough.
11. Timing of getting into groups
You could put them in groups first so that they know it is a group game and to make sure they won’t forget the game rules while moving their chairs around. Alternatively, you could explain the whole game while they are still facing the front of the class and you have their attention, and then get them to move into groups.
12. Right group sizes
This means both deciding if that activity is generally best done in pairs, threes, fours etc (pairs means more speaking per person but there might be a lack of ideas and no audience or monitor for two people doing a roleplay), and whether there are particular people who would be better off in a group of a different size (because they only like working with one particular person, because no one wants to work with them so people take turns one at a time, because they dominate groups that are too small etc.)
13. Variety of group sizes
This keeps students interested and on their toes, and tests their communication skills in slightly different ways for each group size. An unusual way of adding a bit of variety is to combine twos into fours, then fours into eights etc in activities such as a pyramid ranking debate.
14. Variety of ways of organising the group
Another way of keeping them stimulated is to use different methods of getting them into groups such as making them stand in a line by the date of their birthday and then splitting them off into groups by counting along that line. I have written another whole article on this subject for TEFL.net.
15. Using the right classroom language
This can mean choosing the best language to explain how you want them to get into groups or, more unusually, actually choosing how you want them to get into groups so that you can use particular language. This can be chosen by their language level, by language you have recently presented, by language that you want to present to fit in with the textbook, or by language you have chosen to improve their general level of understanding of classroom language.