Major factor in the Actual Value of a bike is the amount of money that must be spent to repair it.
with that in mind:
replacing the worn out chain and cassete will increase the value by about 80$ (60$ if it was a freewheel)
new brake pads will increase the value by about $50
replacing the dead bottom braket will increase the value by about 60$
trueing a bent wheel increases the value by about 25$
new tires 35$ each
saddle about 30$
small accessories, ie bottle holder, increase value by less than 10$
cleaning doesn't increase the bikes value at all, since it can be done at no cost

So, the largest value increase is from replacing the worn out chain and cassete. do that first
Alternately, if you don't have the time or inclanation to do such repairs, deduct the amount listed for each applicable item from your asking price. Don't be surprised to see it fall into negative numbers, in which case just sell the bike as scrap metal or donate it.