Which verbs use etre and which use avoir in the past tense, and why?

The past tense is constructed in 2 parts: 1) the auxiliary 'avoir' or 'être' is conjugated in the present + 2) the past participle of the verb. The majority of verbs use avoir in the past tense (e.g. j'ai mangé; ils ont fini) and there are only a few verbs that use être, but they are very important to know & understand. The most helpful way I found to remember which verbs use être is to memorise them, using the helpful mnemonic DR MRS VAN DER TRAMP: D-devenir R-revenir M-monter R-rester S-sortir V-venir A-aller N-naitre D-descendre E-entrer R-rentrer T-tomber R-retourner A-arriver M-mourir P-partirAdditionally, it is helpful to note that not only are these être verbs mostly verbs of movement, but many are opposites of each other (e.g. naître- to be born & mourir-to die) which can also help you if you remember.