Here is a shortened version of a great post.

Quality Chess

From the Quality Chess Blog by GM Aagaard

Recently I have felt compelled to consider what the properties of the ideal chess trainer should be. Obviously there are a few different types of chess trainers, each with their own function. Let’s have a look at them:

a) The Junior Trainer
This starts with teaching children the rules, notation and so on, then goes on to teaching them basic strategic concepts, such as development, king safety, the value of the pieces.

The junior trainer will often go through games with a group of children, discussing ideas, telling them when to look out for simple opportunities and so on.

b) The Talent Trainer
In this phase of the talent’s development the trainer is likely to still be a stronger player, at least for a part of the process. He is able to show the talent a lot of ideas and typical patterns, structures, combinations and so on. At the same time he will also be able to help the talent prepare for games, analyse his games with him and choose what books he needs to read, which types of exercises he should solve and so on.

This is the standard trainer you can find online.

c) The Second
Once a player reaches a certain level he will start to play in tense competitive situations. This can be national championships, international championships or even matches.

I think most players over 2400 would benefit a lot from a second, but with the low amount of money in prizes at “normal” tournaments, only players at the top or participants in junior championships usually have access to a second.

d) The Grandmaster Trainer
The final category is the one I have moved into over the last decade, by natural progression.

In 2006 I started working with Sabino Brunello. He was rated 2400 and had just fulfilled the requirements for the International Master title. Our relationship was at the time quite similar to b) above. I still had a number of things I could teach him. For example, I realized that his strengths did not fit well with his 1.e4 repertoire and I encouraged him to learn 1.d4 and use it at an opportune moment where the surprise would come in handy.(Much more-see whole post)