Hello. I see this is a decently older thread and there are some great comments regarding your inquiry. I am new here, but not new to magic or dealing with “spirits”. I am NOT a LARP’er. I was plagued by spirit visitations as a child and my mother always told me they were demons. Without going into depth of my life, I grew up with an aversion to dealing with any kind of spirit, thus my path has focused on energy work, thought forms and mental magic. I found I also had a natural propensity to impact my environment without spells or requests of spirit intervention.
What I am getting at is maybe diving straight into evocation, or invocation, of spirit entities is not the way to start for you. One consensus of over the years is the need for and use of energy. Try a Chaos magic book, particularly one that focuses on practical application of energy. Build your energy capabilities and astral awareness. Take up and engage in an initiatory path first, such as Asenath Masons “Draconic Ritual Book”, excellent for a neophyte who has some LHP knowledge. Whatever path you take though, it will take time and effort.
Even with my natural ability and spirit sensitivity, it has taken time, study and practice, practice, practice. Natural born athletes still need to practice and engage in their art to hone and keep their skills sharp. Just as they have physical muscle memory to perform, we can build mental and spiritual muscle memory. Certain actions performed for a consistently long enough period will become second hand. Until then, however, you must put in the time, study and commitment to perform, even when not successful. The magical arte is not an easy path and honestly it is not for everyone; nor is everyone capable of performing it let alone mastering it.
Take into consideration the good advice here and be discriminating in your consideration of it as well; not all of it is helpful. Find an initiatory path and a mentor. Above all, persevere. May the fates be with you… 
