It has been stressed so much upon istikhara in Hadith. While intending to do anything, seeking advice from Allah is called istikhara. The Prophet (صلی الله عليه وسلم) has said that it is an unfortunate thing not to seek advice from Allah (not to do istikhara). If a person marries or makes a journey after doing istikhara, he has to feel no regret. The mode of doing istikhara has been written in Behishti Zewar, vol. 2 page 33, you should read it. If you are unable to understand anything, you should ask us.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband