What stops one from complete surrender? Do one's past negative sanskārs and vāsanās play a part in determining the level and speed of surrender? How can one overcome one's inherent negativities and make progress towards self-surrender faster?

Surrender is not a one-time procedure. It is not that we surrender once, and we are done with it forever. We have to keep surrendering at every moment. In this process, there are innumerable obstacles. Our mind is made of Maya and it naturally runs towards the world. We need to beat this mind with the intellect. We also have saṁskārs of past lifetimes that must be countered. And then, we have the ignorance or agyān within us, which is the source of all the problems.

However, we must not feel disillusioned. Innumerable souls in the past have overcome these obstacles to perfect their surrender to God, and have attained Him; if we endeavor sincerely, we too will be successful.

First, we must illumine our intellect with the spiritual knowledge given to us by our Guru. Then, with this purified intellect we must work on the mind, to detach it from the world and attach it to Names, Forms, Pastimes, Virtues, Abodes and Saints of God. Along with our sincere efforts, we must pray to God and Guru for help, firmly believing that Their Grace can make us perfect our surrender.

To speed up the process of surrender, we should strengthen the sentiment, "God and Guru alone are mine." When we develop love for God and Guru, surrender becomes natural and automatic. When we reach the state of complete surrender, the feeling "He alone is mine" will always remain in our mind, and all our thoughts and actions will be in consonance with it.

If we can keep increasing our desire to serve, that is also a very potent tool for progress. Jagadguru Shree Kripaluji Maharaj states:

सौ बातन की बात इक, धरु मुरलीधर ध्यान।
बढ़वहु सेवा-वासना, यह सौ ज्ञानन ज्ञान।  

"Fix your mind on Shree Krishna, and keep increasing the desire for sevā. This is the most powerful weapon for conquering the mind and Maya."