"The Martians took a risk landing in populated areas.
In a remote spot they could have assembled the heat ray weapon before any armed response could arrive."

Very good point, Keith! You are quite correct. Their best bet would have been to make their landings in a remote area, as you say, where they'd have time to assemble their fighting machines without human interference.

It would not, however, have made for such a dramatic story line.

The various tactical adjustments the Martians made were interesting. At first they were potentially at a distinct disadvantage, depending on how fast the humans reacted, because the heavier gravity made it difficult for them to move around effectively...until their fighting machines were assembled. That appears to have taken them perhaps 10 or 12 hours of work.

They then discovered that the humans' artillery guns *could* destroy a Martian machine if they scored a hit in the right place (the hood which contained the operator). It wasn't easily done, but it could happen, so hidden artillery guns became a problem for the Martians, and they temporarily retreated back to their base, where they came up with a solution to nullify the hidden guns.

And so on...

Really quite interesting how they adapated quickly to each challenge as it came along. The British Army tried hard to do the same thing, but was simply outclassed by superior Martian technology.

In the long run, however, I suspect the humans could have made things very difficult for the Martian occupiers through guerrilla tactics rather than direct, open warfare. There weren't very many Martians in the landing force...perhaps 100 individuals at the most (if each cylinder contained 10 occupants) and they were vulnerable to weapons, just as we humans are, so I think that the Earthlings would have eventually found ways to make their occupation untenable, killing them off individually one way or another with explosives and all manner of other weapons. The Martians would never have felt safe in a world containing literally millions of people willing to devote themselves to killing just one Martian, any way they could manage it.

Their best bet in such a case would have been to strike a deal with *some* of the humans, getting them to fight the other humans, in return for getting a comfy place in the New Order, Martian style! And that is exactly what colonial powers always do to subdue a Native population. They hire some of the Natives to police and control the others! (Wells even touched on this hypothetical notion briefly at one place in his story...)