The largest critical factor for success is to quickly make decisions but firmly refuse to change them when challenges emerge based on the decisions you have made.
Make up your mind quickly with as much information as you can access. But set your mind on achieving your aim without wavering. This will make it difficult to second guess yourself.
Failure, on the other hand is almost always underpinned by sluggishly made decisions that hastily get changed at the slightest bit of opposition.