How to achieve regioselective (base-catalyzed) enolization of a carbonyl group in a diketone?
As @Zhe and @Zenix have mentioned, you have to hope that there is a difference in the rate of enolate formation to differentiate the two ketones. 

To do this cool a rigourously dried solution of the diketone and a trapping reagent ($\ce{Me3SiCl}$ if you're doing an anhydrous workup otherwise TIPS-Cl or MeI) to $\mathrm{-75 \, ^\circ C}$ and slowly add 1 eq. of LDA keeping the reaction mixture cold. This will trap the first formed enolate (kinetic enolate). Allow to warm, dilute with hexanes, filter (or wash with aq if you used TIPS or MeI), concentrate and analyse. 

If this gives a mixture then you try making the more stable (thermodynamic enolate) and trap that. This means forming the enolate without the trapping compound ($\ce{Me3SiCl}$, MeI or TIPS-Cl), giving it time to equilibrate then adding your trapping compound. This might be done with NaH in dry DMF, left to stir at $\mathrm{-30 \, ^\circ C}$ for an hour then the trap is added, worked up and analysed. 

Even then with this example I think you'll get a mixture, but you don't know until you try. If you do get a mixture then you have to rearrange your synthetic pathway so that you don't have this problem - you'll probably have a different one but that's the  way it goes!