What determines how good a person is at remote viewing?
Psychology. This is a big word that covers a lot of areas, including:
Innate talent. A great deal of medical and psychological study has been done on this subject. There may be certain markers of persons most likely to be good at it. This doesn’t mean others can’t do it well or those with such markers for certain will, only that there are some general indicators -- and some evidence that ‘talent’ is indeed a critical factor. "World-class talent" as some refer to it, is estimated to be in about ½ of 1% (.005) of the population. However, this doesn’t mean that talent varying from very high to minor is not found in the rest of the population.
Belief systems. This is tough to measure, but it’s easy to measure the effects of psyche problems via lack of accurate performance. Commonly a significant drop in apparent ability follows an initial period of experience with RV, which is thought to be psychologically based. This ranges in the easy zones from fear at the ability (‘power’), fear it may be ‘evil’ in some way, fear of releasing personal privacy boundaries, and disbelief in its possibility (despite personal evidence).
In the more difficult to handle psyche areas, the issues may have more to do with an inability to handle the repetitive destruction of psychological reality-models that close exposure to psi experience brings. This is usually the largest danger (mental, emotional and physical) from the experience of moderate to advanced remote viewing, is that a viewer will not be able to integrate the massive psychological structure changes required; this can lead to actual illness if viewing is pursued without resolving such a cognitive dissonance.
In most cases it simply leads to a viewer ceasing to practice, or ceasing to practice in protocol (so the mind has other ‘options’ for explanation), or ceasing to pursue RV altogether. This is so common a side effect that ‘serious RV skill’ is not often found demonstrated publicly -- not even in groups which specialize in psi training and practice.
Tenacity. This word covers a few areas: that of a viewer’s ability to ‘stick to’ working in proper protocol; the ability to ‘stick with’ RV through an often long spell of apparent lack of ability and other frustrating periods; and the ability of a viewer to enforce proper practice (and documentation) with themselves constantly over a long period of time.
Objective Integrity. The process of learning how one’s mind works, and in revising (repeatedly) mental structures related to reality, requires an extraordinary amount of self-discipline, ability to be objective about oneself, ability to discern personal changes and emotional instabilities and deal with them, and so forth. This is the last on my list of what is required, but it is actually the first on the list of the most common problems that "public" remote viewers seem to suffer from: a lack of proper emotional, mental balance and objectivity can over time literally lead to varying degrees of schizophrenia.
You might have noticed that talent and practice were both subsumed under the ‘psychology’ heading. I did that because in my experience, what talent can manifest depends mostly on psychology (and in fact, the measure of talent really might be much more a measure of what psychology lets talent through than talent itself); and what practice will be done properly and consistently over a period of time will depend both on innate psychology and on the psychological response to practice.
It is critical to note that the majority of psychological issues are best avoided or ‘dealt with’ by working in protocol. Doing this consistently provides a good bridge for belief and validation, while also preventing a great deal of assumptive-delusion that can come from working outside it. Every (without exception) person I have encountered who had obvious problems stemming from their RV practice, had abandoned -- or never even been introduced to -- protocol and the fundamental reasons for it.
Anybody can offer to teach you RV protocol or psi methods to use in or out of it. But nobody can promise you that in the long run, you will be a remote viewer at all, let alone particularly good at it. This is an extremely individualized experience, and success -- regardless of training or talent -- can be credited only to the Viewer themselves.