Being of service in the true sense is expressing the divine love that you experience in your own practice in the world - lighting up the world around you. This can be done in many ways. But it is important that the love is flowing.
In order for one to serve, one must first recognize a definite need. One must observe a given need, with clarity. If a need is not recognized with clarity, one might be intervening unnecessarily.
One must distinguish between that which is a true need and that which is a base desire. Experience is the teacher, if one can observe clearly.
If one has thirst, one will recognize when another thirsts.
If one has hungered, one will recognize when another hungers.
If one has angered, one will recognize when another is angered.
If one has suffered, one will recognize when another suffers.
One can only be of service if one has experienced what another is experiencing.
One can allow ones emotions to rule a situation, or one can allow ones inner heart to rule a situation.
If one allows ones inner heart to rule, one can then "Be of service".
The qualities within ones inner heart, must be allowed to serve.
One will then be serving in a self-less manner.
One then serves to simply be serving.
Ones intention is then focused upon self-less duty.
Only when there is no loss or no gain, can one experience "Being of service".
There is a good chance then, to recognize precisely Who and What one is serving.
"Do unto others, as you would have others do unto you."
Might this describe "Self-Realization"?
Might this describe "Unity"?
More than likely!