Be careful not to travel on Friday afternoon close to dark, even if Shabbos food is prepared for you. Many times it could happen that you won’t arrive at your intended destination before dark. You will be stuck on the road and may come to chillul Shabbos. (MB3)
If late in the afternoon you are traveling through a village where you can stop and get ready for Shabbos, do not allow the yetzer hora to convince you to take a risk to make it to your destination. (MB3)
If it happened that night fell and you managed to arrive within the techoom of the city during bain hashmashos, you can get out of your vehicle and walk to your destination. (MB3)
If Shabbos comes and you find yourself in an unsafe place (e.g. on the road) you are allowed to travel as far as you need to settle in a safe place. (ShA1 – MB5)
If you ordinarily eat a seuda like Shabbos every day, make the Shabbos day meal recognizable by holding it at a different time. (BeH “she’ayno”)
Do not have a sit down seuda, out of the ordinary, any time on erev Shabbos (nor erev Yom Tov) – you will ruin your appetite for the Shabbos night meal. (ShA2 – MB8)
If it is a seudas mitzva for a mitzva that occurs on Friday (e.g. a mila, pidyon haben, wedding) it is allowed. If you can make it in the morning it is better. (Rama2 – MB9,13)
Eating snacks at a Friday engagement party is allowed. However a seuda to celebrate an engagement is not a seuda mitzva. (MB9)
A seuda to celebrate the conclusion of a masechta is allowed on Friday. It is proper to postpone any seudas mitzva, if possible. (BeH “oh” – MB9)
Having a seuda for a bris mila or pidyon haben is a mitzva but not an absolute requirement. (BeH “muttar”)
Whenever you are eating a seuda on Friday, beware not to fill yourself to the extent that you won’t be able to eat the Shabbos night meal.(BeH “muttar”)
When Purim is on Friday, begin the seuda before the ninth hour. Bedieved, you may begin even after that. (BeH “muttar”)
Are you allowed to eat mezonos after Shabbos morning Kiddush before the seuda? The minhag is to be lenient. There are men of good deeds that are machmir to fulfill the Magen Avraham’s opinion not to eat before the bread meal. All agree that you shouldn’t fill yourself with the foods before the bread meal. (BeH “muttar”)
You are allowed to eat a regular weekday lunch all day on Friday. However, there is a mitzva to save your appetite by not beginning lunch after the ninth hour. (On the short winter days, even beforehand it could ruin your appetite.) Included in this mitzva is not to drink a lot of alcoholic beverages after the ninth hour. (ShA2 – MB14,17)
Do not fast on Shabbos so you will not enter Shabbos feeling afflicted. Exception: If you are sensitive to feeling full to the extent that any eating during the day will ruin your appetite for a night meal, then it is a good minhag to fast. (MB18)
A taanis tzibbur that occurs on Friday (e.g. Tenth of Teves) must not be broken before tsais hakochavim. (Rama4)