On level 139 you need to focus on collecting power-ups, preferably those more powerful than firecrackers as they will have the most impact. Do not rush into using the bombs though – try to get a couple of power-ups close to each other and activate them in a single move. This will clear more space and will charge the Lightning power-up faster.
It is also possible to get two Lightnings nearby on this level. In this case you can try matching them as it will bring you an instant victory! Check out this video.