I use a few approaches that as a whole will, I hope, prepare my students for an actual encounter. Firstly there is sparring. Sparring is important because it familiarises you with not only getting hit but also having punches and kicks thrown at you. Second, we drill techniques so that they become almost automatic. The last thing is a form of one step my teacher invented for us that we affectionately call the "Circle of Death". The process is as follows: one person stands at the middle of a circle of the rest of the class. In turn each person in the circle makes an attack against the centre person. It can be any form of attack (though we haven't as yet tried it with weapons) which must be dealt with effectively and efficiently by the centre person. This continues in rapid succession until all people in the circle have attacked, then we change so that each person has a turn in the centre.
The Circle of Death teaches my students to be aware and prepared for any form of attack. It also gives them an opportunity to make practical us eof the techniques they drill for so long.
One thing I always tell my students is: do not anticipate a particular attack. Either attack or react to your opponents attack. Too many times have I seen someone anticipate an attack and begin a block or parry only to find they have reacted too soon or to the wrong perceived signal and taken a smack in the mouth or a kick in the guts.
We use the circle of death also. We also have and alleyway, the class is split and lined up facing each other on both sides of the dojo, one student stands with his face to the wall while the instructor designates who's going to attack, the student then turns around and walk betweent the two lines, not knowng who is going to attack, how many attackers there are going to be, or how they will be attacked, at the end of the alleyway he takes his place at the end of the line and the next person is up. There are several variation in both drills, weapons, multiple attackers, attacks from the rear, etc.