Clean coils and other components with vacuum.
Change filter, if necessary.
Check for loose electrical connections in unit and tighten as necessary.
Clean and wipe any excess dust or dirt and oil as required.
Oil motor bearings as necessary.
Check operation of fan motor for excessive bearing wear.
Check operation of all controls, such as PE switches, dampers, damper operators, and thermostats.
Clean surrounding area, record results and findings and report any needed repairs or operational adjustments.

Obtain and review manufacturer's instructions.  Follow manufacturer’s instructions or procedures if different to these instructions or procedures.
Disconnect, tag, and lock out electrical circuit.

Standard and Phillips head screw drivers-various sizes; Pliers-vise grip (2), slipjoint, needlenose, diagonal; cutting pliers, side cutters; Ball peen hammer; Hack saw and spare blades; 3/8' drive socket set and ratchet; Small set of Allen wrenches; Assorted center punches, drift punches, and steel chisel; 12' measuring tape; Crescent wrenches 4" to 8";  Open and box end wrenches ¼" to ¾"; File; Pipe wrenches to 14"; Small level and square; Pocket knife; Flashlights; Grease guns and oilers; Wire brush; Extension cord and inspection lights; Various cleaning tools - brushes, scrapers, etc; Emery cloth.
Vacuum
Oil
Lubricants. 
Consult the Material Safety Data Sheets (MSDS) for hazardous ingredients and proper personal protective equipment (PPE).
Gloves.