Paper is 200g or more(for the finished page) in b4 format (or b5, your choice. B4 is just more common). Any pencil is fine I think, also is useful having a cyan pencil that doesn't get in the way when you're scanning the pages. For inking, you can choose between more fluid or more dense inks, fluid usually is easier to use. Traditionally, mangakas use dip pens, G-pen and maru-pen types are the most popular, but there are others. Then, you'll need white tempera color or white-out correction fluid not only for correction but also to paint white details and such.
And of course you have screentones, which in my experience are not cheap at all and it's a good idea to use digital ones instead. If you want to go full traditional, you'll need a cutter to cut and scrape the screentones.
Usually there are 6 panels per page. To know the most common compositions of panels, the best thing is... to read lots of manga. Unless you're going to draw yonkoma, which has only 4 panels.
Also, when painting black big areas, rechargeable brush-pens are a good chioce.
