General rules to observe Shravana vratam:
On the day of fast (vratam), one must bath in the morning
For Oppiliappan, only food prepared without salt must be partaken
Only once on that day food must be partaken, if needed, on can take fruit based diet during the second part of the day.
One can visit temple to worship Perumal
Recite Stotras
A general rule for the Vratam
One should avoid entertainments on that day
Avoid wearing new clothes
Vratam should be observed by adhering to the above rules and most importantly one should contemplate on Perumal during the observance.