Compatibility & Faith:- Life is long, probably he/she is going to be a part of your life for the next fifty years. It will be a hell of a roller coaster ride. Make sure there is a mutual compatibility and should be God fearing and stay under the umbrella of faith and peace with God :)
Adjustment capability:- You see the entire human race is flawed. We were made by the almighty like that. You are incomplete. I am incomplete. We are incomplete. But marriage as a constitution is all about accepting each others flaws and adjust as much as possible. If you are Indian, the process becomes a bit more long, you have to accept each others families flaws too.
Beauty:- The moment I said beauty, the first image formation in the cerebrum part of your brain was something similar to ‘Taylor swift', if you are an Indian and have taste similar to me. But understand this, beauty is not just skin deep. After a certain point in our life, how we look just stops to matter. That is the reason, your grand parents don't spend their money for getting a facial done. Look for a beautiful soul, your marriage will last a bit longer than forever.
Sorted up finance:-
The truth is, no matter what you call me, money will always be an important aspect. If you are not financially stable(either alone or after combined efforts by counterpart) the marriage is ultimately going to fail. I am a civil engineer and I know how weak foundations turns out later. You cannot even imagine while laying it, the damage it can bring to your structure.
Loyalty:- I am a loyal person. If you are with me, I can bloody take a bullet for you right on my chest. I will die protecting you. But, I have some expectations. If I am loyal to you, you better be loyal to me. This is the kind of attitude which both counterpart must possess. Make your dog jealous of your loyalty, that's tough though.
Unrealistic expectations:- It's good to expect a bit, the problem arises when it gets unrealistic. It's already difficult to survive in this harsh competitive world. Don't expect your counter part to be romantic 24*7. Every single soul is struggling. Make the struggle easy, not difficult.
Messed up mentality:- I have seen some brides expecting the groom to immediately leave his parents and live isolate to provide a ‘personal space'. Honestly speaking, that's a messed up mentality. He was raised with them, do let him live in peace. He deserves it.
Unrealistic demands:- If she is working 9–5 and cooking meals for you and your family. The least you can do is, help her a bit to lift her mood up. If you can't cook, at least cheer her a bit, she deserve it.
I hope you find the imperfect yet perfect one soon :)