depends how mechanically minded you are . when i had a shop it scared me how seemingly smart looking people lacked the grasp of even the simplest of things
there are a few specialist tools needed
lets start from a bare frame
headset cups need to be fitted into the headtube , ghetto method is with some soft wood that covers the area of the cup and knock in with a hammer . pro is the park headset tool . everyman method is a long bolt , nut and suitably large washers to screw the cups in
putting the forks in ( inch or inch/eighth , threaded or threadless ) common sense for assembling the open or sealed ( not really sealed ) bearings . steerer might need to be cut . hacksaw and file or pipecutter . threaded headsets will need some large spanners . the crown race will need setting on the forks a specialist tool is needed here or a tube a fraction larger than the steerer
the bottom bracket needs a specific tool for whatever type you use . shimano cartridge needs the cartridge tool . some have a lockring so a C spanner is needed ( butchers use a drift and hammer ) cup and cone need again a large spanner . a tape measure is a good idea for chainline
cranks will need either an 8mm allen key ( hex wrench ) or a 14mm ( or is it 15mm , been a while since ive used bolts ) socket . chainring bolts need a chainring bolt tool
pedals will be 15mm , you might luck out and a spanner fits but most dont and a pedal spanner is needed . plus it sucks when the normal spanner snaps and you punch the floor
a vernier caliper is a wise tool to have as its worth checking everything that fits to anything , its proper use determins whether your a guy screwing a bike together or a pro
theres a selection of tools needed for the cassette/freewheel . various different splines used by various different companies over the years . if its a cassette you will need a chain whip ( or make one )
chain tool
proper torque settings are worth learning
of course theres the 2mm - 8mm allen keys ( hex wrench ) . spanners . cable cutters . grease . degreaser . rags . chain lube . gt85 . thread lock . copper grease . pump . hmm what have i forgotten
this is of course just the bolting on of bits . theres also the correct use of greases/loctite not to mention the setting up of brakes/gears and the various bearings
the park tools site is a good source of information
theres this
http://bicycletutor.com/
sheldons site is mandatory for every cyclist
http://www.sheldonbrown.com/