Originally Posted by kunsunoke

Assuming you decide to tear down and rebuild, you may need to pick up some special tools and some consumables.
If the crankset is a cottered-type, you'll need a cotter press to avoid damage to the cotter pins or cranks. If it's cotter-less type, you will need a threaded crank puller to get the crank arms off of the spindle.
The bottom bracket may require a pin spanner for the non-drive side bearing cup, and an appropriate removal tool for the drive-side cup. Bearings may be loose-type or caged.
The headset will require purchase of an appropriately-sized headset wrench (to work the headset upper cup), and an adjustable wrench for the top nut.
Getting the stem and seat tube out of the frame will require a set of metric Allen hex keys, and also a small rubber mallet (to free up the stem wedge).
Hub rebuilds are going to require 13, 14, 15 and/or 16mm cone wrenches.
Truing of the wheels will require a good spoke wrench (at the very least).
A set of cable shears and an awl will help immensely with cable replacement.
Replacement of the clincher tires and tubes will require purchase of a set of nylon tire irons.
A bicycle stand and wheel truing stand are optional, but make working on the bike much easier.
Plan on getting some waterproof grease, Tri-flow (or similar) lubricant, some replacement shifter and brake cables and housings, cable crimps, replacement 700c tubes (and maybe tires), a tire patch kit, and decent-quality brake pads. The bar tape may also require replacement. You'll also need 1/4", 3/16" and/or 5/32" ball bearings (preferably Grade 25 or lower) if the ones you currently have are rusted/pitted.
YouTube is your friend when it comes to tutorials on how to tear down and rebuild bicycles. The C & V forum is as well, of course.