Wudu

It is prescribed to say Bismillaah according to the majority of scholars, but they differ as to whether it is obligatory or Sunnah. If one remembers to say it, it may be said either at the beginning of wudoo’ or during it.

It is mustahabb to say, when one has completed wudoo’:
“Ashhadu an laa ilaaha ill-Allaah wahdahu laa shareeka lah, wa ashhadu anna Muhammadan ‘abduhu wa rasooluhu
I bear witness that there is no god except Allaah alone with no partner or associate, and I bear witness that Muhammad is the Messenger of Allaah.”

The Prophet (peace and blessings of Allaah be upon him) said:
“There is no one among you who does wudoo’ and does it properly and does it well, then he says, ‘Ashhadu an laa ilaaha ill-Allaah wahdahu laa shareeka lah, wa ashhadu anna Muhammadan ‘abduhu wa rasooluhu,’ but the gates of Paradise will be opened to him and he may enter through whichever of them he wishes.” (Narrated by Muslim, al-Tahaarah, 345).

A report narrated by al-Tirmidhi adds: “Allaahumma ij’alni min al-tawwaabeena wa’j’alni min al-mutatahhireen
O Allaah, make me one of those who repent and make me one of those who purify themselves.”
(al-Tahaara, 50; classed as saheeh by al-Albaani in Saheeh Sunan Abi Dawood, no. 48)
Source

This is a Du'a I have in my book, Ta'leemul-Haq. Its the du'a while making wudhu:
"Al-laa-hum-magh-fir-lee-zham-bee wa-was-si' lee fee daa-ree wa baa-rik lee fee riz qee"
"O Allah! Forgive my sins, and give expansion (abundance) in my home and grant me blessings in my sustenance." (Ta'leemul-Haq)
and Allah, The Most Forgiving, Knows Best.
Wasalam
-SI-