GTB. Guess the banzuke. Can't live with it, can't live without it. Or as Kintamayama says these days, can't live with it. The dichne.com entry form is a bit unwieldy for guess composition, in my humble opinion. This explains the success of the newfangled GTB Helper, but since its debut, it's also made me wonder how you people make your guesses.
Here's my way. Long story short, all old-tech, three pieces of paper. I am quite anal about it. Meticulous is a nicer word, but a less accurate one.
So, three pieces of paper. One is an A4 sheet, the other two are consecutive pages of an A4 notebook, preferably the kind with the spiral coil thing; in any case, the two consecutive pages must belong to different sheets, i.e. the first one has to be on the left side and the second one on the right, so that they're simultaneously visible when the notebook is left open.
(N. B.: A5 notebooks are a waste of trees, too big for pockets and too small for anything more grand.)
The standalone A4 sheet is to copy the completed basho's makuuchi banzuke, usually from sekiwake down, with the W-L records of each rikishi. Below that I write part of the juryo banzuke layout, but only fill in the shikona and records of the rikishi that stand a chance of promotion to makuuchi.
Here the notebook comes into play. First, on the right page, I make the next basho's makuuchi banzuke layout (looks like the SumoDB one; rank in the middle) and fill in the Y/O, which are straightforward and require no calculations at all. Then I cross out the spots on the west side of the layout that are vacant (Y2w, M17w this basho).
Once that's finished, I move to the left page and, checking the A4 sheet as I go, I jot down the "by the numbers" rank the rikishi deserve in about one and a third columns, one below the other; I always put down the number maegashira rank followed by E/W, komusubi being "maegashira 0" and sekiwake "maegashira -1". An exception is made for the promotees from juryo, where I jot down a range of ranks they apparently deserve according to past banzuke.
Next, I fill in the following basho's banzuke guess (right page) rikishi by rikishi from sekiwake descending, using the left page rankings, checking the previous basho's banzuke to make sure I don't promote MK or demote KK. When I get down to the promotees from juryo, I stop being 100% religious with my by-the-numbers ranks and just try to make it look as reasonable as possible. When that's done, my guess is good to go.
So how do you people do it?