This paper presents techniques used in combinational test generation for multiple stuck-at faults using the parallel vector pair analysis. The techniques accelerate a test generation procedure previously proposed and reduce the number of test vectors generated, while higher fault coverage is derived. The first technique proposed in this paper, which is applied at the first phase of test generation, is rules of ordering vector pairs to be analyzed, to derive high fault coverage without repeating the analysis for the same vector pairs. The second one is to generate new vector pairs for undetected faults, instead of random vector pairs. Both techniques are based on the idea that faults close to primary inputs should be detected earlier than close to primary outputs. The third technique proposed here is how to construct vector pairs from one input vector in order to accelerate test generation especially for circuits with many primary inputs and scan flip-flops. Experimental results for bench-mark circuits show the effectiveness of the techniques.