How can I learn to take care of an old (70s era) road bike/get it back to working condition? I found my mom's old road bike from the 70s tucked away in a corner of our attic. It's not in great condition and is pretty rusty. I don't know a lot about bikes from a mechanical or upkeep point of view but would love to use this bike as an opportunity to really understand them and work on my bike mechanics skills.
It's doable although it doesn't make sense from a cost perspective. Only do it if you have an emotional investment in the bike or want a fun project that will teach you a lot about bike mechanics.

To give you an idea, I bought a 1975 Peugeot UO18 Mixte (a woman's road bike, perhaps similar to your mom's) that had been stored in a barn and turned it into my commuter bike. In order to do this, I had to (in order of simple to complex):


Replaced the brake pads which had oxidized. 


Easy. You just need an adjustable wrench or set of open-ended wrenches (maybe a screw-driver). There are different styles of brake pads, it's best to remove the old ones and bring them to your local bike shop so they can give you the right replacement.

Replace all of the brake lines and derailleur lines, which had seized.


Easy-to-moderate. You need to get your brake/shifter housings cut to length which your bike shop will do for you. Replacing brake lines is fairly easy although you need to readjust your brakes after you do this. Rather than cutting the brake line to length (which needs a special tool), you can have the bike shop cut and crimp it after you're done. No special tools needed except screwdrivers, wrenches, and the aforementioned cable-cutter which is optional. Having a brake "third hand" will make your life a bit easier although asking a family member for their physical third hand also works.   Replacing derrailleur lines is a little bit more tricky and not recommended until later on as you'll need to readjust the derailleurs after replacing the cable.

Replaced the old steel front and rear wheels (rims, cassettes, sprockets) with 700c rims with a nice modern cassette in the back and a nice dynamo in front. New tires and tubes too, of course, as the old ones had rotted away.


I could have kept the rims but they were steel and not very "grippy" in the rain; in addition, the old size limited my tire options. I knew that I wanted a dynohub and so it was just cheaper in the long run to just go straight to buying new wheels front and rear. It also allowed me to go from 5 speeds in the rear to 9 speeds.
Easy to moderate. Even if you don't replace the rims, you'll likely need to replace the tires and tubes.  Replacing the front tire is fairly easy. You do have to get a new tire on the bead, which will require tire tools (get the Pedro levers). Replacing the rear is also pretty easy, just watch how to snake the chain around the rear sprockets. You'll also need a pump too, of course.

Replaced the chain with a 8/9 compatible chain


Moderate. You'll need to get a chain-breaker tool and replacement pins.

Replaced the front stem (the old French AVA stem is prone to snapping) and bars with contemporary Velo Orange components.


Easy. Just needed a set of hex wrenches.



These were the "basic" mods. In addition, I also changed out the rear derailleur with a nice Campy one and changed out the shifters to a nicer set of vintage Shimanos.  But these are optional.

Now the overall cost for my bike was much more than if I had bought a decent used bike (I estimate more than ~$300 in parts and several hours of labor) but less than what a new, steel-frame commuter might be (~$800). The advantage in my case is that I live in a high-theft city and this commuter doesn't look too fancy but rides like a dream. And I like fixing things.



If you're a beginner, the only real "essentials" would be to make sure that your tires have air, the cranks work, and that you can brake. After that, everything else can be a slow upgrade as you learn more skills as a mechanic.

In terms of resources, I'd recommend Sheldon Brown's site, the Zinn book on maintenance, and the Park "Blue" book. And of course, a lot of hanging around at your local bike shop.

It might also help if you can find someone to mentor you as a fledgling bike mechanic. I know it's hard as a gal who loves to get my hard hands dirty to find any respect, but it's possible to find community. See if there are any community bike clinics offered at your local bike shops or in the area. 



Here is the bill of materials / notes from my repair notebook:

Front wheel
700c  vuelta rim  622x18
Stainless steel spokes 36h
Sanyo 6vac hub dynamo NH27

Rear wheel
SRAM PG950 9-speed Cassette  SR-PG950-34      11X34 $18.39
2012.11.21  Dimension Road Rear Wheel 700c 36h Shimano 2200 Silver / Freedom Ryder 23 (622-17)Black 

Front sprocket (original), crankset original, pedals original
52-38

Rear Sprocket 
SRAM PG950 9-speed Cassette  SR-PG950-34 (was 14-26) 382g
11-13-15-17-20-23-26-30-34

Derailleur
Campagnolo Mirage (used/vintage)
Chain wrap  = (52-38) + (34-11) = 14 + 23 = 37

Stem and bars
Velo Orange Threadless Stem Adapter ST-0001 $16
VO Porteur Handlebar $32

Upgrade Schedule
2012.09.26: Front Suntour derailler. Put new chain on (7.96mm outside width)
2012.10.09: Replaced front wheel with Dynohub + 700c 622x18 (36h) $85
2012.10.09:  Continental Gator Hardshell Urban Bicycle Tire with Duraskin (700x28, Wire Beaded) $48.79                  
2012.10.18: Rear Campagnolo (8-9) derailler  
2012.10.24: All new brake lines and derailleur lines (Jagwire L3)
2012.10.24: 15.6kg w rack and dynohub and lights, front sun tour derailleur, rear campy derailleur.
2012.11.28 sks mud guards     
2012.11.21  SRAM PG950 9-speed Cassette  SR-PG950-34      11X34 $18.39
2012.11.21  Dimension Road Rear Wheel 700c 36h Shimano 2200 Silver / Freedom Ryder 23 (622-17)Black
2012.12.01  Rear wheel =&gt; Continental Gatorskin ($49.99)