An invocation is like a ticket for a train, and if you can't find the train there isn't much point in having the ticket. Opening the Gates gets you to the doorstep of magical consciousness, but it is the invocation which gets you onto the train and propels you to the right place, and that isn't something which "just happens" unless you have a natural aptitude for the aspect of consciousness you are invoking. However, it does happen; people tend to begin their magical work with those areas of consciousness where they feel most at home, so they may well have some initial success. Violent, evil people do violent and evil conjurations; loving people invoke love - most people begin their magical work with "a free ticket" to some altered state of consciousness, but in general, invoking a specific aspect of consciousness takes practice and I don't expect immediate results when I invoke something new. If interminable tracts of deathless prose work for you, then fine, but I find it hard to keep a straight face when piety and pomposity combine to produce the sort of invocations to be found in print. I name no names.
I can't give a prescription for entering magical consciousness. Well devised rituals, practised often, have a way of shifting consciousness which is surprising and unexpected. I don't know why this happens; it just does. I suspect the peculiar character of ritual, the way it involves the senses and occupies mind and body simultaneously, its numinous and exotic symbolism, the intensity of preparation and execution, involve dormant parts of the mind, or at least engage the normal parts in an unusual way. Using ritual to cause shifts in consciousness is not exceptionally difficult; getting the results you want, and avoiding unexpected and undesired side-effects is harder. Ritual is not a rational procedure. The symbolism of magic is intuitive and bubbles out of a very deep well; the whole process of ritual effectively bypasses the rational mind, so expecting the outcome of a ritual to obey the dictates of reason is completely irrational. The image of a horse is appropriate: anyone can get on the back of a wild mustang, but reaching the point where horse and rider go in the same direction at the same time takes practice. The process of limitation described in these notes can't influence the natural waywardness of the animal, but at least it is a method for ensuring that the horse gets a clear message.
Suggested free e-books to read:
Aleister Crowley - The Invocation Of ThothJames Eschelman - Invocation Of Horus