Here are 3 tips that should help you perfect your French pronunciation of 'papier':

• Break 'papier' down into sounds: say it out loud and exaggerate the sounds until you can consistently produce them.
• Record yourself saying 'papier' in full sentences, then watch yourself and listen. You'll be able to mark your mistakes quite easily.
• Look up tutorials on Youtube on how to pronounce 'papier'.

To further improve French pronunciation, we suggest you do the following:

• build up your vocabulary & learn grammar: Always study French with audio. Written French and spoken French are almost 2 different languages. There are many silent letters, glidings, liaisons etc… and they are everywhere, including in French verb conjugations and grammar.
• learn to use contractions: instead of saying 'tu as', drop the 'u' of tu and say 'ta' (eg: tu as soif → ta soif) This is true for any verb that start with a vowel. (tu es belle → te belle, il y a → ya, c'est a dire → c t a dire, etc). Drop the 'ne ' in negative sentence (eg: je ne vais pas sortir → je vais pas sortir)
• Learn the casual question form which consist of the statment (with no inversion) with a rise in your intonation at the end. (eg: as tu l'heure? → tu as l'heure? → ta l'heure?)
• Subscribe to 1 or more French teaching channels on Youtube: it's free and it covers the core topics of the French language. Check out Vincent and Alexa channels to name just a few.