Two Light but Heavy Words and Morning and Evening Due Thanks

"Two words that are light on the tongue but so heavy on the Scales of good deeds," according to the Prophet, pbuh, are:

"Subhan Allahi wa Behamdihi"

i.e.
Exalted is Allah and thanks are due to Him.

This is a very good tasbeeh (mentioning of Allah).

(Preferably said 100 times in the mornings and evenings. They help wash one's
sins away.)

Morning and Evening Due Thanks

"Allahumma ma asbaha bee min ni'matin, aw bi-ahadin min khalqika, fa-minka wahdaka
La shareeka lak,
Falakal-hamdu walaka-ashukr."

‘O Allah whatever blessing I or any of Your creation have risen upon is
from You alone,
You have no partner,
so to You is all praise and unto You are all thanks."

(Remember that all tasabeeh should not be mere mindless repetitions by the tongue, otheriwse they are in vain, but recognitions and acknowledgments of the heart.)