Istikhara is a sort of seeking guidance from Allah SWT, when you are unable to decide about a lawful matter. Istikhara is not to be done for each and every thing because it was not intended for that purpose. Usually we should use our common sense and AQL/intellect and weigh things properly, to decide about them, However, for any reason or under any circumstances, if we are unable to make a decision, then we can seek the help of Allah SWT by doing Istikhara.
WAY TO PERFORM ISTIKHARA:
First pray Two Cycles (raka') of ritual Prayer (nafil) such that in the first raka' after Surah Fatiha (Allhamd…) recite Surah al-Kafirun (Chapter 109) and in the second raka' after Fatiha (Allhamd…) recite Surah al-Ikhlas (Chapter 112). After finishing prayer recite this (supplication/dua'): Dua in Arabic Text above.
Transliteration: Allahuma inni astakhiruka bi'i3lmika, wa astaqdiruka biqudratika, wa as'aluka min fadhlika-l'a3zeem, fa innaka taqdiru wa la aqdiru, wa ta3lamu wa la a'a3lamu, wa anta a3laamu-l'ghuyub Allahumma in kumta ta3lamu anna hatha-l'amr (and here he mentions his need) khayru-lii fi diini wa ma3aashii wa a3aaqibati amrii faaqdirhu lii wa yassirha lii thumma baarik lii fihi wa in kunta ta3lamu ana hatha-l'amr (he mentions his need) sharru-lii fi diini wa a3aashii wa a3aaqibati amrii faasrifha a3nii wa asrifni a3nhu wa-qdir lii al-khayra haythu kaana thumma raddhinii bihi
TRANSLATION: "O Allah! I seek goodness from Your Knowledge and with Your Power (and Might) I seek strength, and I ask from You Your Great Blessings, because You have the Power and I do not have the power. You Know everything and I do not know, and You have knowledge of the unseen. Oh Allah! If in Your Knowledge this action ------------------------------------------------ (which I intend to do) is better for my religion and faith, for my life and end [death], for here [in this world] and the hereafter then make it destined for me and make it easy for me and then add blessings [baraka'] in it, for me. O Allah! In Your Knowledge if this action is bad for me, bad for my religion and faith, for my life and end [death], for here [in this world] and the hereafter then turn it away from me and turn me away from it and whatever is better for me, ordain [destine] that for me and then make me satisfied with it."
How many times?
It depends. Sometimes it takes only once to get the answer and sometimes it takes longer. It is better to do istakhara seven (7) times. If you have received an answer as explained in the section below, stop doing istikhara. You do not have to continue to do isitkhara for 7 days. It is better that right after reciting the supplication, given above, sleep with ablution (people who cannot keep the ablution for longer times due to health problems do not have to worry about ablution before falling asleep) facing the direction of the Qibla (facing the Qibla is not required but it is a Sunnat of our beloved Prophet Peace Be Upon Him). It is better to recite salutations (durood/ salawat) on the Prophet Allah's Grace and Peace be upon him before and after the above Dua (supplication).
Answer:
If in the dream one sees whiteness (means any thing white in color, for example: milk, white paper, white sky, white clothes, white light etc.) or greenness (means any thing green in color, for example: grass, plants, trees, green clothes, green light etc.) then understand that this task is better and if one sees redness (means any thing red in color, for example: blood, red clothing, red fruit, red light etc.) or blackness (means any thing black in color, for example: black water, black light, black clothings, black sky, black wall etc. ) then understand it is bad and avoid it.
If do not remember any dream or do not see any colors then follow your heart. Whatever intention grows stronger in your heart regarding your targated work follow it after seven days of Istakhara.
inshallah I'll keep u in my du'aa. May Allah make eveything easy for u, both in this life and the hereafter. Ameen 
