Praise be to Allah.
You should note – may Allah help us and you to do that which He loves and which pleases Him – that du`a is a weapon that has been forsaken by many people, but du`a is worship.
It was narrated from al-Nu’maan ibn Basheer (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: “ Du`a is worship.” Then he recited (interpretation of the meaning):
“And your Lord said: Invoke Me [i.e. believe in My Oneness (Islamic Monotheism) and ask Me for anything] I will respond to your (invocation). Verily, those who scorn My worship [i.e. do not invoke Me, and do not believe in My Oneness, (Islamic Monotheism)] they will surely enter Hell in humiliation!” [Ghaafir 40:60].
Al-Albanisaid (it is) saheeh. See Saheeh Sunan al-Tirmidhi, no. 2685.
And it was narrated that the Prophet (peace and blessings of Allah be upon him) said: “There is nothing dearer to Allah than du`a.” Classed as hasan by al-Albaniin Saheeh Sunan al-Tirmidhi, no. 2684.
And he (peace and blessings of Allah be upon him) said: “Whoever does not ask of Allah, He becomes angry with him.” Classed as hasan by al-Albani. See Saheeh Sunan al-Tirmidhi, no. 2686.
If you understand this, you should be keen to make a lot of du`a.
Secondly: There is etiquette to be followed when making du`a and there are things which should be avoided, some of which we will sum up as follows:
1-Starting with oneself when making du`a.
2-It is mustahabb to raise the hands when making du`a.
3-The person making du`a should be in a state of complete purity.
4-He should face the qiblah when making du`a.
5-He should manifest humility before Allah (“call upon Him in humility and in secret” [al-An’aam 6:63 – interpretation of the meaning]). In Badaa’i’ al-Fawaa’id Ibn al-Qayyim said that not being humble when making du`a is a kind of overstepping the mark in du`a. (Badaa’i’ al-Fawaa’id, 3/12).
6-He should beseech Allah in his du`a.
7-He should not look for a speedy response. In al-Saheehayn it is narrated that the Prophet (peace and blessings of Allah be upon him) said: “You will be answered so long as you are not in a hurry and say, ‘I made du`a but I did not receive a response.’” Narrated by al-Bukhaari, 6340; Muslim, 2735. For when a Muslim calls upon his Lord, one of three things happens, as was mentioned in the hadeeth of the Prophet (peace and blessings of Allah be upon him): “There is no Muslim who calls upon his Lord with a du`a in which there is no sin or severing of family ties, but Allah will give him one of three things: Either He will answer his prayer quickly, or He will store (the reward for) it in the Hereafter, or He will divert an equivalent evil away from him.” They said: “We will say more du`a.” He said: “Allah’s bounty is greater.” Narrated by Ahmad, 10749; al-Tirmidhi, 3573. Classed as saheeh by al-Albaniin Mishkaat al-Masaabeeh, 2199.
8-It should be noted that one should praise and glorify Allah in du`a, and send blessing upon the Prophet (peace and blessings of Allah be upon him). It was narrated that Faddaalah ibn ‘Ubayd said: The Prophet (peace and blessings of Allah be upon him) heard a man making du`a after his prayer, but he did not send blessings upon the Prophet (peace and blessings of Allah be upon him). The Prophet (peace and blessings of Allah be upon him) said: “This man is in a hurry.” Then he called him and said to him or to someone else: “When any one of you has finished praying (and makes du`a), let him start by praising Allah, then let him send blessings upon the Prophet (peace and blessings of Allah be upon him), then after that let him ask for whatever he wants.” Al-Albanisaid: it is a saheeh hadeeth. (See: Saheeh Sunan al-Tirmidhi, 2765.
Thirdly: With regard to overstepping the mark in making du`a, this involves a number of things:
1-Being too detailed in one's du`a, as described in the question (“O Allah, give me a furnished apartment and a colour TV etc”). Rather what is prescribed is to make du`a in concise words as the Prophet (peace and blessings of Allah be upon him) used to do. He used to ask Allah for the best in this world and in the Hereafter. It was narrated from ‘Abd-Allah ibn Mughaffal that he heard his son say: “O Allah, I ask You for the white palace on the right side of Paradise if I enter it.” He said: “O my son, ask Allah for Paradise and seek refuge with Allah from the Fire, for I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: ‘Among this ummah will be people who overstep the mark in purifying themselves and in making du`a.” Narrated by Abu Dawood, 690; classed as saheeh by al-Albaniin Saheeh Abi Dawood.
2-Calling upon Allah in ways that Allah has forbidden or that are means that lead to something forbidden (because the means come under the same rulings as the ends). This was stated by Ibn al-Qayyim in Badaa’i’ al-Fawaa’id, 3/12. So whatever is a means to something haram is also haram.
Usually those who use televisions use them to watch and listen to haram things, so if the person who is praying for that is one of these people, then his du`a for this TV is a kind of overstepping the mark in making du`a, because he is asking Allah to give him something by means of which he will disobey Him.
So it is clear that this du`a is overstepping the mark in two ways:
1-Because it is detailed
2-Because it is a means to something haram, and the means come under the same rulings as the ends.
This applies if the person who is making the du`a is going to use it for something haram, as most people do.