First 10 Days Of Zul Hija
It is said that "there are no days more loved to Allah (SWT) for you to worship him therein than the first 10 days of Zul Hija." During these days, deeds are superior and more beloved then deeds that are done on regular days. The Prophet (PBUH) said "There is no day in which Allah (SWT) liberates more servants from hellfire than the day of Arafah which is the 9th day of Zul Hija."
For those people who have not yet gone for Hajj or Umrah, there are a few things you can do from home to gain great reward. First, during these 10 days of Zul Hija, it is sunnah to say Takir(Allahu Akbar), Tahmeed(ALhamdulilah), Tahleel(La ilaha ila Allah) and Tasbih(Subhan Allah). For men these phrases should be recited out loud where it is permitted to mention Allah's name. Women should recite these phrases quietly. These phrases should be recited all day and night until Eid prayer. As well as after each of the 5 prayers on the day of Eid. One of the best dua'a is the one said on the 9th day of Zul Hija (the day of Arafah) "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 ilaha ila Allah, wahdahu la sharika lah, lahulmulk, wa lahulhamd, wa howa ala koli shayin qadeer"
The second way to gain great reward is by fasting. Whoever fasts one day for the sake of Allah (SWT) during the first 10 days of Zul Hija, Allah (SWT) will place between him/her and hellfire a trench with a distance that is equivalent to the distance between the sky and earth. Allah (SWT) says "All the deeds of the sons of Adam are for him, except for fasting, which is for me and I am the One who will reward him for it." Each day fasted during the first 10 days of Zul Hija is equivalent to fasting one year and to offer Salatul-Tahajjud (late night prayer) during one of the first 10 days is like performing late night prayer on the night of power(Laylatul Qadr). Which takes us to the third way of gaining great reward.
The third way of gaining great reward is by doing Qayam Il Layl(Night Vigil). If someone enlivens any night of the first 10 days of Zul Hija, it will be as if he had performed the same worshipful service ibadah for the sake of Allah as someone who not only performs pilgrimage(Hijj), but also performed the visitation(Umrah) throughout the entire year.
2 more ways to gain reward is by doing Qurbani(the slaughtering of a sacrificial animal). The slaughtering of a sacrificial animal is usually done on the 10th day of Zul Hija or on the days of Tashreeq which are the 11th, 12th or 13th day. This is the sunnah of Prophet Ibrahim, when Allah, the most High, redeemed Ibrahim's son by the great sacrifice of an animal in his place. It is said that the number of hairs on the animal, is the number of sins that will be forgiven if a person sacrifices an animal and feeds the poor with the meat.
The final, but certainly not the last way to gain great reward is by At-Tawbah(repentance). One of the most important things to do during these 10 days is to repent sincerely to Allah (SWT) and to give up all kinds of disobedience and sin. Repentance means coming back to Allah (SWT) 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 (SWT) loves.