Making up Obligatory Prayers
With regards to your prayers:
[1] Make a reasonable, safe estimate of the number of prayers that you think you have missed
[2] Make a manageable schedule, and pray them consistently, without fail
Strive to complete them as they were due (with the sunna actions) and making the intention of drawing closer to one’s Lord.
Making up Obligatory Fasts
As for your obligatory (Ramadan) fasts, you will need to:
[1] Perform a single expiation. The expiation is to fast sixty consecutive days. Ensure that either `Eid does not fall in one’s sixty day period.
[2] Next, make a reasonable, safe estimate of the number of fasts that you think you have missed. Do this by:
[a] Assuming there are thirty days of Ramadan each year
[b] Counting the number of years of Ramadan between puberty and the time one is reasonably sure that one was fasting the whole month. (For example, 15 years would be 450 fasts)
[c] Making a reasonable, safe judgement on how many of these were valid and how many were not. (For example, assuming 5 fasts were valid each year, 300 fasts would need to be made up)
[d] And then commit to fasting them until you lift them entirely from your dues.
[Shurunbulali, Maraqi al-Falah; `Ala al-Din `Abidin, al-Hadiyya al-`Ala’iyya]
Turning to Allah
Use this whole period of your life as a juncture of turning to Allah, realizing the words of the Prophet (Allah bless him and give him peace), “The one who repents from sin is like the one who never sinned.” [Ibn Maja], and committing to becoming the strong believer — firm in faith, and rooted in action.
And Allah alone gives success.
