One of the best, if not THE best work written on sending salutations upon the Prophet (Sallalahu Alaihi Wassalam) is the Qawl al-Badi of Imam al-Sakhawi, the reknowned student Hafidh Ibn Hajar al-Asqalani. The best available edition is by the hanafi hadith scholar residing in Madinah al-Habibah, Sheikh Muhammad Awwmah al-Madani, may Allah Most High facilitate meeting the sheikh and benefitting from his work, Amin.
Since childhood I have been told to recite darud sharif when i had lost something and could not find it. Rather than being a baseless indo-pak custom it has a basis in the shariah as I discovered when i found the following when skimming through the contents of Qawl al-Badi, Imam al-Sakhawi said on p.227:
“As for salat upon Him for one whom forgets something, or wishes to remember something, and likewise for the one fearing forgetfulness, on the authority of Anas (Allah be pleased with him) who said: the Messenger of Allah (Sallalahu Alaihi Wassalam) said: “If you forget something then send salat upon me and you will remember it with the permission of Allah Taala”, reported Abu Musa al-Madini with a weak chain. On the authority of Uthman bin Abi Harb al-Bahili that the Prophet (Sallalahu Alaihi Wassalam) said: “Whomever wishes to say something but then forgets should send salat upon me for his salat upon me is a substitute for that which he wishes to say, and perhaps he will remember” reported like this by al-Daylami and its chain is weak….
On the authority of Abu Hurayrah (Allah be pleased with him) who said: “Whom so ever fears forgetfulness for himself should make abundant salat upon the Prophet (Sallalahu Alaihi Wassalam)” reported by Ibn Bushkawal with a broken (munqati) chain.”