If I were to have a generally earth like world, with water and land masses very similar, what could you add to make storms happen more often, and more specifically, lighting storms. I know lightning happens because of friction in the clouds between dust particles, but could increase the amount of lightning strikes on a planet?
There are some places on Earth that have an unusually high frequency of lightnings. For instance, Venezuela. The explanation, in this case, consists in moisty air locked by mountain ridges, and then sent onto a cycle of heating and cooling, where charges are likely accumulated at the two ends of the cycle in a phenomenon that is reminiscent of a Van Der Graaf generator.
My suggestion would be to make a large number of smaller, nearly land-locked, seas on your new world, with high coastal mountains, and nearly dust free to reduce the albedo. Also, increase the tilt, so that a larger portion of the surface may get maximum solar heat at some point during the year.
Next, cover the coastal mountains with some moisty jungles to make the air above richer in water, and increase the salt in the sea, to create a drier column of air over the sea. The difference in moisture should create a barrier for the electrostatic charges to complete a full-cycle, hence accumulating a difference of potential across the difference in altitude.
The surface of this poor planet will probably look greener than Earth, and like as if the planet were a (greenish) Swiss cheese, or, perhaps, affected by a bad form of acne.
"Activity on the sun significantly increases the rate of lightning strikes on Earth, say researchers, making it feasible to predict when lightning strikes will become more frequent. They discovered that when streams of high-speed solar particles strike the Earth's atmosphere, the average number of lightning strikes increased by 32% for more than a month afterwards. The study is the first to implicate the solar wind – the stream of particles launched from the sun at over a million miles per hour – in triggering lightning, a phenomenon that has puzzled scientists."
The original paper is here: http://iopscience.iop.org/article/10.1088/1748-9326/9/5/055004
In summary: it was previously assumed that galactic cosmic rays (GCR) was a source of lightning, and the solar wind helped shield the Earth from their effects, however the study which included 16 years of data shows the opposite effect. For 4 to 5 days after a solar event the amount of lightning drops, but that is followed by a period between 8 and 40 days after the solar event where lightning activity increases.
The researchers suggest some mechanisms involving the solar wind alone, and the solar wind interacting with GCR, but they admit they do not know the actual reason.
Put more energy in the atmosphere: storms are more frequent in summer because there is more solar energy available, and that solar energy is able to lift icy particles and droplets higher in the atmosphere.
This motion helps building up charges in the clouds, which then result into lightning.