Ibadah-Worship to do on the blessed 1st Ten Days of Dhul-Hijjah Fasting - Salat and Dhikr for these Blessed Ten Days

“There are no days more loved to Allah for you to worship Him therein than the ten days of Dhul-Hijjah. Deeds are multiplied in these days. It is during these days that deeds are superior and more beloved, then deeds done at other times. These deeds are superior even to jihaad .

Increase your acts of worship, your remembrance, and your supplication throughout this great day. This is a day in which salvation from the hellfire is within your reach. The Prophet (saw) said, "There is no day in which Allah liberates more servants from the hellfire than the Day of Arafah-9th of Dhul-Hijjah" 

Note:-These are the days of Hajj and Umrah, but what do the people who haven't gone ?

1st as much Dhikr of :-Takbir,Tahmid,Tahleel and Tasbih in the 1st Ten Days of Dhul-Hijjah Dhike below:-

Allahu Akbar, Allahu Akbar, Lã ilãha illallãhu wallahu Akbar, Allahu Akbar, Walil lahil hamd. 

"Allah is the Greatest, Allah is the Greatest. There is no deity besides Allah and Allah is the Greatest. Allah is the Greatest and all praises are for Allah only."

It is Sunnah to say Takbir ("Allahu akbar"), Tahmid ("Al-hamdu Lillaah"), Tahleel ("La ilaha ill-Allah") and Tasbih ("Subhaan Allah") during the first ten days of Dhul-Hijjah, and to say it loudly in the mosque, the home, the street and every place where it is permitted to remember Allah and mention His name out loud, as an act of worship and as a proclamation of the greatness of Allah, may He be exalted. Men should recite these phrases out loud, and women should recite them quietly.

Recite them at all times of night and day until the time of the Eid Prayer., and after the (five) obligatory prayers that are performed in congregation. This begins from Dawn (Fajr) on the Day of Arafah (the 9th of Zul-Hijjah) for those not performing Haj, and from Noon (Zhur) on the Day of Sacrifice (10th of Zul-Hijjah) for those performing Haj (pilgrims); and it continues until Asr prayer on the last day of the days of Tashreeq (Days of Tashreeq 11,12, 13th of Dhul-Hijjah).

Note: Takbir at this time is an aspect of the Sunnah that has been forgotten, especially during the early part of this period, so much so that one hardly ever hears Takbir, except from a few people. This Takbir should be pronounced loudly, in order to revive the Sunnah and as a reminder to the negligent.

Ibn `Abaas commented on the verse …and to mention Allah's name plentifully on Known days [22:28] by saying: …these known days are the ten days of Dhul Hijjah.

Extra Dua
The best supplication is the one on the day of Arafah -9th of Dhul-Hijjah Day of ‘Arafa , and the best thing which I and the prophets before me have said is, ‘There is no god but Allah alone who has no partner; to Him belongs the dominion, to Him praise is due, and He is Omnipotent (able to do all things)
 

( La ilaaha illallah wahdahu la sharikalah, lahulmulk, wa lahulhamd, wa huwa ala kulli shay in qadir)

2.Fasting:-Whoever fasts one day for the sake of Allah, Allah will place between him and the Hellfire a trench equal to the distance between the sky and the earth. Allah says: ‘All the deeds of the son of Adam are for him, except for fasting, which is for Me and I am the One Who will reward him for it.

Fasting any of the 1st ten Days of Dhul-Hijjah each day is equivalent to fasting one year and to offer Salatul Tahajjud (late-night prayer ) during one of its nights is like performing the late night prayer on the night of power Layatul Qadr)"

For each and every day you devote to fasting, you will be credited with the freeing of a hundred slaves , with a hundred she-camels for you to guide in caravan, and with a hundred mares for you to ride in fighting for the cause of Allah.

When comes to the Day of Tarwiyya -8 th of Dhul-Hijjah, and you Fast then you will be credited with the freeing of a thousand slaves , with a thousand she-camels for you to guide in caravan, and with a thousand mares for you to ride in fighting for the cause of Allah.

Then, when it comes to the Day of ‘Arafa - 9 th of Dhul-Hijjah, and you Fast then you will be credited with the freeing of two thousand slaves , with two thousand she-camels for you to guide in caravan, and with two thousand mares for you to ride in fighting for the cause of Allah. Fasting on this day will forgive for the sins of two years, that is, You will also be credited with keeping the fast in the year before this one, and in the year to come after it .'

Fasting the day of `Arafah-9th Dhul-Hijjah Forgives (ONLY) all Minor sins of two years: a past one and a coming one. And fasting the day of `Ashura' Forgives the sins of the past year . Tradition

Fasting is Sunnah to fast on the ninth day of Dhu'l-Hijjah.

3rd Qiyam al-Layl-Night Vigil:-…Salatul Tahajjud ( late-night prayer ) during one of its nights (in the 1 st ten days of of Dhul-Hijjah) is like performing the late night prayer on the night of power-Layatul Qadr"

If someone enlivens any night of the Ten Nights of Dhul-Hijjah by keeping night vigil, it will be as if he had performed the same worshipful service-ibadah, for sake of Allah, as someone who not only performs the Pilgrimage-Hajj, but also performs the Visitation-‘Umra throughout the entire year .

If someone devotes one day to fasting, during 1st Ten Days Dhul-Hijjah , it will be as if he had devoted the whole of the year to the worshipful service of Allah (Exalted is He) and keeping Qiyamal-Layl-Night vigil on one of those nights is like Qiyamal-Layl keeping Night vigil for one whole year .

Ritual prayer Salat of 4 rak'at that is traditionally recommended during the 1st Ten Days Dhul-Hijjah

 

Doing plenty of voluntary (nafl) righteous deeds of worship like Prayer, Charity, reading the Qur'an, Commanding what is Good and Forbidding what is Evil, and other such deeds.

4th Qurbani- The slaughtering of a sacrificial animal is also legislated for the Day of Sacrifice (10th) and the Days of Tashreeq (11th, 12th and 13th). This is the Sunnah of our father Ibrahim - when Allah, the Most High, redeemed Ibrahim's son by the great sacrifice (of an animal in his place).

The number hairs is the numbers of Sins that will be forgiven if a person Sacrifice animal and feeds the poor with the meat.

5th At-Tawbah (repentance) and abstaining from disobedience and all types of sins, since forgiveness and mercy are the results of deeds. Disobedience is the cause of being far away (from Allah, the Most High) and repulsion, while obedience is the cause of being near (to Allah, Most High) and His love.

Sincere repentance. One of the most important things to do during these ten days is to repent sincerely to Allah and to give up all kinds of disobedience and sin. Repentance means coming back to Allah and foregoing all the deeds, open and secret, that He dislikes, out of regret for what has passed, giving it up immediately and being determined never to return to it, but to adhere firmly to the Truth by doing what Allah loves.

If a Muslim commits a sin, he must hasten to repent at once, without delay, firstly because he does not know when he will die, and secondly because one evil deed leads to another.

Repentance at special times is very important because in most cases people's thoughts turn towards worship at these times, and they are keen to do good, which leads to them recognizing their sins and feeling regret for the past. Repentance is obligatory at all times, but when the Muslim combines sincere repentance with good deeds during the days of most virtue, this is a sign of success, insha'Allah. 

Sa it says in the Qu'ran "But as for him who repented, believed and did righteous deeds, then he will be among those who are successful." [al-Qasas 28:67]