Some things to make chances better that transactions confirm quickly:
Make sure that your transaction is valid (not a double spend)
Try to get your transaction propagated as fast as possible after attaching it to the tangle (i.e. check if you can do PoW with GPU which can be noticably faster than CPU)
Broadcast your transaction to a (full) node that is (as seen from the network) near you and not too overloaded
Make your transaction at a time when the network is not overloaded (too many transactions compared to full nodes). You can see current confirmation statistics at analytics.iotaledger.net/stresstest.table.
But how well you may try, as the consensus algorithm is probabilistic, you might get "unlucky" and your transaction getting ignored (or you accidentally approve a transaction that later gets revealed as invalid). In that case, it helps to reattach your transaction or to reference it from another transaction yourself (the latter is currently not possible from the GUI wallet).