Clean The Outer Unit Condenser (That Thing With Fins /Jali) Blwo Dry It 1st And Wash Blow Condensor With Mild Pressure Water....Then Blow Dry It Again...
Clean Inner Unit Filter...Open Front Panel..Remove...Dry Clean It With Brush And Get Lint Out....Blow Dry With Blower...
Using Tooth Brush...Slightly Clean Inner Evaporator Fins...Blow Dry Them...Install Filter.....
This is Basic Regular Maintenance....If You Feel Lack Of Cooling Still After This...You Maybe Low On charge.....! Usually Dont Mess Wit Unit Its Working Fine...Just Repeat This Procedure Every Year And It Will Be Fine