Assalamu Alaikum wa rahmatullah wa barakatuhu
The sign of the acceptance of supplication is that we accept our destiny, for the moment that Allah sends down on our hearts tranquility and contentment, then our supplication is surely answered, because in such case Allah casts into our heart what makes us feel that we are beyond need of the thing we ask for and it no longer crosses our mind.
A great consolation to every supplicant whose prayer is not yet answered, for there are voices that Allah loves to hear, therefore He tells His Angels to postpone His servant’s need to hear his dear voice calling on Him. Perhaps yours is a voice dear to Allah.
Remember these conditions of Supplication while making your du’a.
• You must know that only Allah(SWT) can answer your supplication and He is the only one Who can "bring good to you.
Allah(SWT) said: "Is not He Who responds to the distressed one, when he calls Him, and Who removes the evil, and makes you inheritors of the earth, generation after generation. Is there any god with Allah? Little is that you remember"[27:62].
• You must invoke Allah(SWT) alone and no others. Allah(SWT) said: "And the mosques are for Allah (Alone), so invoke not anyone along with Him"[72: 18].
• You must be patient
• You must think: positively of Allah(SWT), must have faith in Him and believe that He has the ability to do anything He wants. Narrated Abu Hurairah radiallahu anhu , Allah's Messenger sallallahu alaihe wasallam said: "Supplicate Allah with confidence He will answer you"[Reported by At-Tirrnidhi].
“O Allah! Be gracious to me in making all difficulties easy, for to make a difficulty easy is very easy for You. And, I ask You for ease and safety in the world and the Hereafter.” (Tabarani)