What means Sewa?

What means Sewa ?
The philosophy of sewa shown by Shri Vallabh is unique.It is quite different from the general concept of Pooja as seen in the Sanatan Dharm.
Shri Vallabh tells us that it is our foremost duty to serve Shri Krishna as he is Lord(swami) and we are his servants(sewak).This is the main concept of sewa.Shri Vallabh has preached this to his vaishnavas.In Chatushloki (the grantha in which the Dharma,Arth,Kama & Moksha of a vaishnava are described) Shri vallabh has taught this thing in the first shloka itself.It is written as such :
Sarvadaa sarvabhaaven bhajaniyo vrajaadhipah
Swasyaaymev dharmohi naanyah kvaapi kadaachana
The meaning of this shloka is that the Dharma (prime duty) of a vaishnava is to always do the sewa of Vrajaadhip Shri Krishna whole-heartedly,barring this there is nothing else a vaishanva must do!!