How to surrender to god? For attaining moksha.in kaliyuga?
If someone wants to surrender to Lord Vishnu then he must have left off all his desires first. Means his/her all expectations, desires, wishes also need to be surrendered to Lord. In order to surrender he must do the following:
You should gift all good deeds (Punya karma phal) to Lord Vishnu:
Means, in our life we all do some good deeds. And in return of our good deeds we get returns/gifts from Lord in form of money, fame, peace etc. This is our divine income that we can only earn from the Lord after doing good deeds. If someone wants to surrender to the Lord then he should gift away all his divine income (punya phal) back to Lord Vishnu. Why should we do that? This implies that you don't want fame, money and other good things that we can get in this world anymore. We pray "that's why (because I do not want the worldly items) I am gifting all my divine income back to you, my Lord!".
If while gifting all your divine (income) you have any kind of greed/attachment in your heart except Moksha then Lord Vishnu won't accept this gift. If there is some feeling in your heart that if I gift away all my divine income to the Lord then I am left with no fame, respect and other good things of life for myself. Because of such thinking Lord will never accept my gift to Him because, Lord Vishnu only accepts if someone really wants to give with all his/her heart.
You should gift away all your sins to Lord Vishnu
After giving all divine income (punya phal) to the Lord one should also give all sin income (papa phal, that we get by doing bad deeds ) also to Lord vishnu. This can be accepted by God only when you have full faith in the Lord and you are determined about not doing any more sins in future. One should tell the Lord " If you want to forgive me about my sins then I will be grateful to you, but, if you want to punish me for my sins then also I accept that punishment with all my heart". After seeing your faith and determination Lord Vishnu will accept all your sins.. meaning he will make you fully pure (sinless).
You should have left all worries
The humans always worry about their present, future etc. If you have surrendered to Lord vishnu then you have no need to take on those worries. And why so? Because if you already have surrendered yourself to Lord then how you can worry about yourself? You can only worry about your Lord now. If your Lord want you to suffer then you must accept all suffering given by your Lord and if your Lord wants you to enjoy then you should do that also. You have to obey whatever your Lord commands. The commands come to you through good incidents or bad ones in your lifetime... means if something bad happens to you then you should accept it by thinking it's your Lord's wish.
Keep thinking about your lord Vishnu
One thing that should keep in your mind foremost is Lord vishnu. While you are thinking (Chinta) about your Lord then don't let anything else distract you. You should forget the whole world and only one thing should remain in your mind and that is Lord Vishnu, nothing else. Your whole mind must be full with Lord vishnu's thoughts so that no other thought can enter in your mind.
Lord Vishnu also tests (Pariksha) of his devotee to check how much they are determined on their words of surrender and how much real faith they have in Him. For that He will put obstacles in your way and also might impose lots of suffering on you to check how much faith/respect you have in Lord Vishnu. So be prepared for that examination to prove that your surrender is not going to break that easily. Lord's examination is not going be that easy. He will test your surrender in all ways possible.
Another important thing is, it is not necessary that you have to make this kind of surrender to Lord Vishnu only to get Moksha. If you are a devotee of Lord Shiv then you should surrender to Lord Shiv and if you are Devotee of Mata Durga/Kali or Devi Lakshmi then you can surrender to them also.
Only Lord Vishnu, Lord Shiva and their wives have power to give Moksha. So to get Moksha you have to surrender to one of them only. But do surrender to one only so that your surrender won't get distracted by diluting your faith in different Gods.
In Chapter 9 of the Gita Krishna says (Swami Nikhilananda translator):
I am the same towards all beings; to Me there is none hateful or dear. But those who worship Me with devotion--they are in Me, and I too am in them.
Even the most sinful man, if he worships Me with with unswerving devotion, must be regarded as righteous; for he has formed the right resolution.
He soon becomes righteous and attains eternal peace. Proclaim it boldly, O son of Kunti, that My devotee never perishes.
For those who take refuge in Me, O Partha, though they be of sinful birth--women, vaisyas, and sudras--even they attain the Supreme Goal.
Fix your mind on Me, be devoted to me, sacrifice to Me, bow down to Me. Having thus disciplined yourself, and regarding Me as the Supreme Goal, you will come to Me.
and in Chapter 18, He says:
Take refuge in Him alone with all your soul, O Bharata. By His grace will you gain Supreme peace and the Everlasting Abode.
Fix your heart on Me, give your love to Me, worship Me, bow down before Me; so shall you come to Me. This is My pledge to you, for you are dear to Me.
Abandon all dharmas and come to Me alone for shelter. I will deliver you from all sins; do not grieve.