Finding Optimal Resistor Combination for Desired Equivalent Resistance
First off, the precision of your resistance value is going to be limited to the resistor's rating.  Consider the list of standard values for resistors with a 5% tolerance.  Any number between 10 and 91 is going to be within 5% of one or two of the preferred, E24 numbers.  Your perfect resistor might even be in your supplies, labeled as one of these.

E24 (  5%): 10  12  15  18  22  27  33  39  47  56  68  82
             11  13  16  20  24  30  36  43  51  62  75  91


Trying to combine resistors in series or parallel will also combine their possible errors, so you may not be getting much closer.  Make sure to measure the resistance of any such construction at the end.

See also:
https://en.wikipedia.org/wiki/Preferred_number#E_series