What do I have to do to get another Rathalos Plate

See topic.

I already:

(I fight him with a Carapace Hammer +)

1) go after him in his hunt quest (I choose the Deserted Island one.)
2) I break his face
3) I break his wingtips
4) I collect his shiny drop

Still no second Rathalos Plate to upgrade my hammer.

I'd like better suggestions to get a Rathalos plate.

esiest way would be to hunt high rank rathalos ;P but as i assume you want his materials right now:

you can get plates from breaking the face(4% chance), carving the tail (3%), from shiny drops (2%) and as a capture reward (2%) and there is also a small chance for it to be a normal quest reward.

so (unless you want to do a full hammer playthrough) use a cutting weapon to get the tail, and then capture him.

Or you could try doing tail runs (again considering you don't do a hammer only run) go in, cut the tail (use shocktraps or if in a team sleep/para status) and just abandon if you don't get a plate from it. it can be faster if you can cut the tail efficiently or if it takes you a long time to take him down with your current equipment.

in the end it comes down to chance though if you get one or not and it isn't called a rare item for nothing.

Tail runs are by far the best way to go in my experience, gunlance or swax are your friends

I did it. A tail run.

I began the five-star Rathalos Hunt in the Deserted Island (much safer than the Volcano Rathalos Hunt.)

This time, I went with a decent water element greatsword, and I focused on his tail until it was no longer part of his body. Then I got him away from it and carved it. PLATE!