When travelling through Laos, you will run into many temples and other religious sites without a doubt. These will always require a particular dress code to be worn before you can enter its premises. Therefore, be sure to prepare in advance and pack very plain clothes that are not revealing or bright so that you can enter the religious sites of Laos.
Additionally, if you are looking to relax by the pool after a long day of exploring, be sure to pack up a set of swimwear as well! If you are staying at a hotel in Luang Prabang, such as the Avani+ Luang Prabang, and you have somehow forgotten to pack your swimwear, the staff may help you procure some as well.