how to put label with data to on the marker of my plot?

Hi I would like to put label with data of the point on my plots, I have already tried to use the function text but the result was not so good because some points were very close. I am thinking if there is some way to put letters instead of markers and then to put something similar to a legend with the name of the point and their values. It would be great to have an example thanks to everyone in advance.

[KL]

Using markers will also look quite the same in that case. You should probably display the texts using annotations where you can use an arrow to show the specified data points.