It is not given to any human being that Allah should speak to him unless (it be) by Inspiration, or from behind a veil, or (that) He sends a Messenger to reveal what He wills by His Leave. Verily, He is Most High, Most Wise. (Qur'an 42:51)
Inspiration could be through many ways, through signs (Qur'an 5:31) which we can see, through dreams (Qur'an 37:105) and also through guidance via Qur'an and the words of Prophet (peace be upon him). We ought to be careful though in deciding if a certain dream or a sign is from Allah as we might not possess a good ability to filter out the good dreams / signs from the bad ones.
Often times we take decisions based on our wisdom, guidance and Furqan (intellect, the ability to decide if something is right or wrong). Isn't it mainly obtained from Qur'an and Hadith?
But those who deny Our verses are deaf and dumb within darknesses. Whomever Allah wills - He leaves astray; and whomever He wills - He puts him on a straight path. (Qur'an 6:39)
So, we need to try as much as possible to read the Qur'an and try to get guidance,
Perhaps the best description of the Quran was given by Hazrat Ali(RA), the cousin of Prophet Muhammad (peace be upon him) when he expounded upon it as,
"The Book of God. In it is the record of what was before you, the judgment of what is among you, and the prophecies of what will come after you. It is decisive, not a case for levity. Whoever is a tyrant and ignores the Quran will be destroyed by God. Whoever seeks guidance from other than it will be misguided. The Quran is the unbreakable bond of connection with God; it is the remembrance full of wisdom and the straight path. The Quran does not become distorted by tongues, nor can it be deviated by caprices; it never dulls from repeated study; scholars will always want more of it. The wonders of the Quran are never ending. Whoever speaks from it will speak the truth, whoever rules with it will be just, and whoever holds fast to it will be guided to the straight path."
We constantly keep asking Allah's guidance in every rakah of every Salah.
All the praises and thanks be to Allah, the Lord of the 'Alamin (mankind, jinns and all that exists). The Most Beneficent, the Most Merciful. The Only Owner of the Day of Recompense(Judgement), You (Alone) we worship, and you (Alone) we ask for help (for each and everything). Guide us to the Straight Way(path), The Way of those on whom You have bestowed Your Grace , not (the way) of those who earned Your Anger, nor of those who went astray.
Sometimes, consulting our friends or near of kin can help. (Qur'an 42:38)
Sometimes, we do not have the complete picture of what could be coming on our way, or we're in a dilemma and are unable to get out of. I think Istikhara is one way which is prescribed by Prophet (peace be upon him).
Narrated Jabir bin Abdullah:
The Prophet (p.b.u.h) used to teach us the way of doing Istikhara (Istikhara means to ask Allah to guide one to the right sort of action concerning any job or a deed), in all matters as he taught us the Suras of the Qur'an. He said, "If anyone of you thinks of doing any job he should offer a two rakat prayer other than the compulsory ones and say (after the prayer): -- 'Allahumma inni astakhiruka biilmika, Wa astaqdiruka bi-qudratika, Wa as'alaka min fadlika Al-azlm Fa-innaka taqdiru Wala aqdiru, Wa ta'lamu Wala a'lamu, Wa anta 'allamu l-ghuyub. Allahumma, in kunta ta'lam anna hadha-lamra Khairun li fi dini wa ma'ashi wa'aqibati Amri (or 'ajili Amri wa'ajilihi) Faqdirhu wa yas-sirhu li thumma barik li Fihi, Wa in kunta ta'lamu anna hadha-lamra shar-run li fi dini wa ma'ashi wa'aqibati Amri (or fi'ajili Amri wa ajilihi) Fasrifhu anni was-rifni anhu. Waqdir li al-khaira haithu kana Thumma ardini bihi.' (O Allah! I ask guidance from Your knowledge, And Power from Your Might and I ask for Your great blessings. You are capable and I am not. You know and I do not and You know the unseen. O Allah! If You know that this job is good for my religion and my subsistence and in my Hereafter--(or said: If it is better for my present and later needs)--Then You ordain it for me and make it easy for me to get, And then bless me in it, and if You know that this job is harmful to me In my religion and subsistence and in the Hereafter--(or said: If it is worse for my present and later needs)--Then keep it away from me and let me be away from it. And ordain for me whatever is good for me, And make me satisfied with it). The Prophet (ﷺ) added that then the person should name (mention) his need. (Sahih al-Bukhari 1166)
May the creator guide us all.