There's a million ways to approach a II-V, so I'll just name a few. The most basic way is to play diatonically. If you're in C then you would play D dorian-G mixolydian. If it's diatonic, then you know that D dorian and G mixolydian are made up of the same notes, so you could just think of it as D dorian or G mix. for the whole thing. I can see that this is going to take forever, so I'm just going to list a bunch of different harmonic devices that people use for II-V's:
D-7|G7|C
D-Maj|G7|C
D-7|D-7|C
G7|G7|C
D-7|D-7 G7|C
D7|G7|C
D7|D-7 G7|C
D-7b5|G7|C
D-7|Eb dim|C/E
D7|Db7|C
A-7 D7|D-7 G7|C
A-7 D7|Ab-7 Db7|C
Ab7|G7|C
Ab-7|Db7|C
Db7|Db7|C
Ab7|Db7|C
Eb-7 Ab7|D-7 G7|C
Ab7|Bb7|C
Eb-7 Ab7|F-7 Bb7|C
F-7|Bb7|C
F#-7|B7|C
Keep in mind that you can change what type of dominant you play. Whenever you see a G7 on this list, you can play it as G mixolydian, G7b9 (G Ab Bb B Db D E F), G7#9 (G Ab Bb B Db E F), G7#11 (G A B C# D E F), G9#5 (G A B C# D# F), and a few other sounds. When you see a D7 on here it probably implies a D7#11 or D mixolydian.
My advice is to not worry about all this stuff and just transcribe what players like Charlie Parker, Clifford Brown, Coltrane, etc. play on a II-V and figure out exactly what type of harmony they are implying. I would also suggest that you sit down at a piano or with a piano player and try to get as many II-V sounds in your ear as you can.
Pretty much all the progressions I listed show up in standards and modern tunes alike, so maybe try to find some tunes that use these progressions and listen until the sounds become familiar to you. Also I should note that many if not most of these are substitutions for a II-V, and when you're accompanying someone, you should use them with discretion. All of them except the last four are common progressions, and the last four are just some other progrssions that resolve to a I chord.
I'm sure I didn't explain this very clearly, so if anyone wants to make corrections, clarifications, etc., please do.