Meditation requires re-allocation of one of the most precious resources we have in our present circumstances, and that's our time. Since its practice involves a sizable chunk of this asset, it would be well worth to check in advance whether a technique we want to use does actually produce results.
Judging the effectiveness of 'spiritual' systems, methods, practices or beliefs is easy. Simply look at the people propagating or 'selling' such techniques, and you'll intuitively sense how far these protagonists have come. Direct attention to what they radiate after their many years of practice, - whether unrestricted expansion is the true theme of their life, or just money-making, or self-aggrandization, or making you adhere to a restrictive way of life.
Tune in if they are aware of their Grand Self, - i.e. if they truly know what they are doing.
If the energy-makeup and insight of the teacher(s) does not genuinely impress you, then wisely evaluate if you really want to invest similar time, energy and money into such exercise.
Or bluntly put: - If after 20 years of practice the teacher looks dull and formal and not anywhere near perceiving advanced layers, then you may safely assume that you - after spending two decades of exercising this technique - might have 'achieved' exactly the same dullness.
Most traditional, or well-known, or socially accepted systems and beliefs are little more than rigid doctrines how meditation or other practices 'should' work, - but in effect never do. Here one either finds taciturn compliance that it e.g. would be insolent to claim any true breakthrough (as in Buddhism), - or wide-spread 'make-believe' where the adherents do claim command of higher powers and perception they never actually have (as in most other 'spiritual' organizations).
Choosing a system of meditation or any other method aimed at shifting focus to 'The Subtle' is not a matter of how much money we spend or whom we pay, - or how intensely we believe in a particular technique, - or of sitting at the feet of a charismatic teacher, - or being part of a social group of similarly attuned souls.
Even if a particular system sports masses of followers, most these 'movements' quietly disappear after several years, usually leaving behind a small group of zealous die-hards who resent to admit that their cherished practice doesn't yield lasting results.
So let your own experience be your key guide.
Get familiar with the mechanisms of your practice to be and then sincerely try it out. If it doesn't yield tangible results within a reasonable period, then forget about it and test the method next in line.
Yet if a particular technique makes you truly break through to the regions beyond senses and mind, - if you are thrilled and ever more enthusiastic for further and higher insight and clarity, - then it's worth pursuing what you are doing to further depths.
Now, - the instructions on meditation found in the Upanishads are vastly different from our present-day ideas how meditation should work, the techniques currently en vogue, and the results their practice is supposed to generate.
Actually the upanishadic ways of meditating may disagree so fundamentally with all you've learned and are used to think about meditation that it may easily irritate you.
But bear with me, - becoming familiar with this new (but actually very ancient) approach spotlights all modern techniques from a remote and exclusive perspective. It allows you to evaluate your expectations, your techniques' scope and claims, and the results you were promised to reach through them in an entirely new light.
And it hands you a powerful tool to access layers beyond your present focus.