If you approach SIN from the northeast, the views of Singapore won't be very good from either side of the plane. If you approach from the southwest, you should have an excellent view from the left side of the plane. Before lining up for an approach from the southwest, you could take either a gentle bank to the left over Sentosa, meaning an even longer good view from the left, or a fly-over and loop-back turn to the right, meaning a decent but far-away view could be had from the right side of the plane.