On erev Pesach one may eat food cooked with matzah crumbs such as stuffed fish (gefilte fish) or kneidlach. However, after the tenth hour of the day one should refrain in order to have appetite for seder night (Mishnah Berurah 471:20). However, one shouldn’t eat cake made with matzah meal as it is forbidden to eat matzah on erev Pesach, and although one can’t fulfil the mitzvah of matzah with cake, if one would be kovea seudah he would recite hamotzi and birchas hamazon, therefore, one should avoid eating it (Shu”t Shevet HaLevi, 8:117, and R’ Shlomah Zalman Auerbach in his he’oros at the back of the sefer Erev Pesach Shechal BeShabbos).
One should cover the tables with plastic table clothes and use disposables.
One must make kiddush and eat bread in the room where the candles are lit, as is clear from Shulchan Aruch (273:7). Nonetheless, R’ Elyashiv rules that if there are electric lights in the room where one made kiddush, then he may light Shabbos candles in another room, and continue his meal there.
Some say that one may use a matzah for lechem mishnah (Igros HaChazon Ish Vol. 1, siman 188). Nonetheless, one should wrap up the matzah and make sure it doesn’t touch the challah, and it can be used as lechem mishnah when wrapped (see Orchos Rabbeinu Vol. 2, pg. 11).
Some say, on Friday night one may be lenient as strictly speaking one may eat matzah then, however, on Shabbos morning when it is forbidden to eat one can’t use it for lechem mishnah (see Shu”t Chelkas Yaakov, 1:92, and Shu”t Betzel HaChochmah 3:110).
One shouldn’t use a matzah from the matzos that he set aside for seder night, as they are presumably muktzeh as one is particular about them, and they are muktzeh machmas chisoran kis. Unless one has lots of matzos, and he isn’t particular if some of them are used up and eaten by young children before Pesach, in which case they aren’t considered muktzeh (see Kaf HaChaim 308, end of 42).
Although the minhag is to eat a minimal amount of challah, one should be careful to eat slightly over a kebeitzah in order to fulfil the mitzvah of seudas Shabbos (Mishnah Berurah 291:2). Additionally, one made a berachah of al netilas yodayim.
If one knows that he won’t eat more than a kezayis, then he shouldn’t recite al netilas yodayim when washing his hands (see siman 158:2).
If one has teeth which crumbs get stuck in and he knows it is hard to clean them, he should dip the challah in water or wine, to soften it and ensure that it doesn’t get stuck.
One shouldn’t dip challah into a container with salt in, rather one should tip some salt out on to the table, in order that breadcrumbs don’t get stuck in the container of salt.
One shouldn’t put challos on the table until his is ready for them, in order that they stay hidden until they are needed - especially when there are young children around.
If one makes kiddush in one place, i.e. on the porch, and eats bread there to fulfil kiddush bemakom seudah [making kiddush immediately followed by a meal], and then he wants to continue his meal with Pesach food and Pesach utensils in another room, one should have intention when washing netilas yodayim that he wants to eat in two places. When he finishes eating, if he can’t see the place where he started the meal, then he should return to the place where he made kiddush and ate bread as bread is something that requires a berachah achronah in the place it was originally eaten. One should also make sure to eat a little bit of bread when returning (even less than a kezayis – see Mishnah Berurah 184:9) before birchas hamazon, as if not, there is a big concern that a berachah is needed on all the food eaten during the meal (besides for meat, fish etc. which come to accompany the bread – see Shulchan Aruch 177:2 and Biur Halachah d.h. she’ein), since one left the bread behind and moved from the place he started eating bread originally (Shu”t Minchas Yitzchok 6:48, and R’ Shlomah Zalman Auerbach, Shalmay Mo’ed pg. 356).
Some offer a solution which would allow one to recite birchas hamazon in the place where he ate the seudah without having to return to the place where he made kiddush, which is that after eating bread in the first place, one should leave a little bit in his mouth, and then go to the place where he plans to eat the seudah, and then swallow the piece in his mouth (see Mishnah Berurah 184:9). However, one needs to be very careful when doing this, as one doesn’t want to be taking food which is chometz into the place where he is eating with Pesach dishes.
