Before 1812-1814, when a printed parish register format was developed for all of Norway, each minister kept his books the way he thought best. If he served more than one parish, he might have divided the record page in half, or in thirds, recording the life events of the parishioners (christenings, marriages, burials) in chronological order for each parish within those lines. Or, he may have listed the name of the parish where he was that Sunday or other day to the side, and simply listed everything in chronological order. Or, he might have divided the register book into half or thirds, pp 1-80 for Parish A, pp 81-210 for Parish B, pp 211-400 for Parish C, and so forth.
In the books kept before the printed format, take a few moments to study the pattern of the records. This will help you be more successful in research. For example, note if the minister is writing the name of the child being christened in larger or different script than the rest of the entry. Is he indenting or out-denting the beginning of each entry, or, does the next entry begin where the last one left off, whether that is in the middle of a line or not? Is he listing the father’s name first, the occupation first, the name of the parish where he is first, or the date first? When you discover the pattern, as your eyes move down the page searching, if something is “out of sync” your mind will let you know-then you can check it out more closely to make sure you haven’t missed any information.
To access free images of the Norwegian parish registers via the Wiki, see the Norway Church Records article in the FamilySearch Research Wiki.
Good luck with your Norwegian research! If you need further help, you can post questions on FamilySearch Forums.