As discussed earlier your mental landscape is a part of you, and a part of the reality you exist within. Mental projections are just energetic extensions of yourself(thoughts and feelings)that may interact with the mental projections of others. We do this subconsciously all the time, unaware that what we are feeling or thinking about is subtly affecting the thoughts and feelings of those around us.
The first step is becoming aware that this subtle interaction is happening all the time. Normally our minds move from one idea to the next fairly quickly, unable to remain still for any length of time. This is where a simple meditation practice can be used to become mindful first of just how much chatter is going on in your head to start with, and learn to reduce the noise down so as to better control your projections. When you are just starting out 15 minutes of quiet solitude is likely to be required in order to help reduce the mental chatter before attempting to project. Find a meditation practice that works for you (there are many and a specific practice is out of the scope of these exercises)
Find someone to work with. It doesn't matter if they are with you, or elsewhere. You will each choose an emotive state to send, and times to send and receive. Take 15 minutes to quiet your mind. There are two common methods to send emotive states. One is to hold an image of the person in your mind experiencing the target state. The other is to send the emotive state directly from yourself to them. For example if you are projecting happiness, you would imagine them smiling, or doing happy things. If you are sending happiness, you would first imagine your happiest thoughts and then send this to them. Your mental imagery should best represent only the individual you are connecting with, or an archetypal representation (when communicating other types of information) for this exercise.
When your time is up, you then contact the person working with you and tell them what you sensed. (You should be sitting quietly while attempting to sense from them). You may find an ability right away, or it may take time for this to develop.