A good trainer must have the skill on the job
A good trainer must have the equipment to train people
A good trainer must train you by putting you on the system to work
A good trainer must be a professional
A good trainer must have a good track record
A good trainers bills should be affordable
A good trainer must have the skill on the job. He must have the skill he is going to pass on to others (his clients, students). That is why some people go to computer school get certificated, and yet know next to nothing, I mean they know just nothing! Find out who their trainer was and he himself must know next to nothing, so, your trainer must have the skills in a high (indisputable) way on the job.

A good trainer must have the equipment to train people. He must have systems, and he must have clients/students use them in the class. If you go to a computer school where you are just writing notes like you are primary school, believe me, you are wasting your time. You dont learn the computer by writing notes. Those notes and hand-outs are useless! Believe me, this is my job and I know what I am saying. You learn the computer by working on the computer by using the computer, by being made to work on the computer. A good trainer must train you by putting you on the system to work, and not by giving you notes or handouts. Check this out it is a secret I just gave you. And even if you need a note at all, those notes are already in the computer, that is they are already in each of those applications we use, the notes already came with the programme as tutorials, they are there in the system, you can always bring them out from the programme anytime you want, read them, and apply them while you are using that very programme to do a job. They are there as a Help tool for the user of the programme. That is the secret those trainers are not telling you which is not fair. So a good trainer must have systems and have his clients use them in real practical work in his class.

A good trainer must be a professional. There must be professionalism of the job. That is, does he take it as his profession? It is one thing to know how to do something, it is another thing to be committed to that thing as a calling and it is yet another thing to be able to teach others that thing. That is where the professionalism comes in, and a good trainer must have it.

A good trainer must have a good track record. You should be able to trail his product and see how well they are doing. He must have a line of products (former clients) who can serve as proof to the good work he/she is doing. In short, he must have a list/line of clients who trained with hum and are now doing well with the skills they acquired from him
A good trainers bills should be affordable

All these can make you judge someone who claims to be a computer trainer to be good or not. Consider them before you enroll with any person/place.
Kinds of training
What if you have succeeded in getting yourself a trainer and you are sure he is good enough to t rain you? There are different kinds of training you could do. They are as follows:
Class Training
Home/Private Training