Firstly - the thing about the 'leap of faith' is that everyone in the world, past and present; religious and atheist; has already made this: the difference between individuals is mostly is whether or not they are aware of the fact of having done so, whether they have done so freely or passively.
Most people are unconscious of ever having made the leap of faith, because most people simply absorb their assumptions from others, without recognising that they are assumptions. Most people regard their basic assumptions as simple facts derived from evidence - but basic assumptions, unlike facts, cannot be contradicted by evidence - because the basic assumptions themselves dictate what counts as evidence; what counts as 'a fact'.
(Evidence is not self-evident; facts do not float around the universe - universally accessible, immediately identifiable as fact, and understood identically and perfectly by everybody... Both depend on prior and basic assumptions concerning the nature of reality.)
What is the leap of faith? Well, it refers to the basic assumptions that make a frame for life and living, for understanding, meaning, purpose and everything else.
Why is it a 'leap' and why is 'faith' required? It is a leap because basic assumptions cannot be derived-from anything more solid than themselves - we need to jump over, or past, or through 'the facts' to reach these assumptions. And it is faith because it rests on something that could be called intuition when it is based on inner sureness, and revelation when it is felt to be given by something external and greater. Perhaps the ideal is that the basic assumptions are mutually reinforced by revelation and intuition.
The word 'leap' also suggests the way that this must be an instant and whole mental move - which also means that that which is known by faith must be simple enough to be grasped and comprehended entire.
Often this requires a preliminary period of critical reflection and clarification to sort-out just what-it-is that we are trying to know as true or false. We must ask the right question before we can get a coherent and correct answer.
What this, in turn, tells us is that a single leap of faith is usually inadequate; especially for a typical mainstream, materialist atheist - who has unconsciously absorbed such a collection of dis-beliefs as to make any single belief incoherent. This is the faith of Modern Man - and typically he cannot tell when, where, how or why he adopted it.
For example, it is quite normal for modern people to disbelieve in the world as having been created, in a creator or any other kind of God, in the soul, in any kind of persistent existence before or after biological life - to disbelieve that reality has any purpose or meaning, and to assert believe that human relationships have no continued reality beyond the lifespan of their participants. Most would regard all human choices and decisions as either random (hence meaningless) or else merely the determined consequences of previous events (hence meaningless) - hence Modern Man does not believe that he has the free agency even to choose his own basic assumptions!.
In other words, typical Modern Men have, unconsciously and uncritically - and indeed generally while denying that any leap or faith has been involved - begin in a situation of so many negations that, if they were to take their own beliefs seriously and consistently, they would be reduced to a state of paralysed and silent despair at the utter futility of everything.
Silent because there could be no meaning in communication, since other beings don't exist, or if even they do exist then communication cannot be possible, and even if communication were possible it could not (in a random/ determined universe) have any meaning.
An essential first step for a leap of faith into meaning and purpose would seem to be to acknowledge that one's assumptions are indeed the consequence of faith, and not of 'evidence'; and to determine to make this leap for oneself, in consciousness and freedom - rather than unwittingly and passively.