something with eyes would make quick progress. because the eye sense is the most developed sense in normal people. as well as eyeballs having the most stamina of all muscles (active non-stop even in sleep).
you get an analog watch that sells for a dollar/pound, cheap. one which moves every second not continuously. watch the seconds with no thoughts. you can't, thoughts will come in. traditionally, the goal is one minute with no thoughts whatsoever. do not shut out thoughts...you can't anyway, just watch the seconds hand...
you can put a coin standing on a table and watch both the whole coin and focus on one side of the coin at the same time. but it has to be a round coin.
you can also gaze at something in front of you like a candle flame, or a small dot on the wall. preferably, it's just a tiny bit higher than eye level and at 1 to 2 meters distance. the goal here is simply to look at the object, to see it
don't strain, keep natural, concentration is simply absorption of mind
20-40 minutes a day. no more or you will run out of energy if you do it daily, which you should; otherwise the gains die down quickly. you are more picking it up daily, before it dissipates, building momentum. studies show this will increase the intelligent quotient by maybe in 10 to 20 point range after a while. after a year or more you can also go for one hour or so, as you are more advanced. eat, sleep and exercise well for fuel.
it will increase everything, from memory recall, even remembering old memories and noticing details that you weren't fully aware back then in the present, but remember now in the future because the conscious mind will increase, as well as ability to control muscles, to tense them and control them. you can make a killing in the gym easier. unsuccessful or unattractive people usually have a low level of mentation, you will notice yours increasing beyond normal range, eventually. this means normal people are usually dull or sleepy tired, but as you increase you just notice their conscious portion of the mind is small. everyone has like a theme or song which is basically a dominant thought train behind their conscious mind. since you're increasing the range of Your conscious mind you can see what is the on the subconsciousness of people...you just pick it up when they move and speak...you will also be more unfrozen yourself, so you can like be a great actor, instantly, change to react as it's appropiate. your emotions will not have inertia that much. . . they turn to be more of a beautiful coloring or a song to your thoughts then being like a tornado / like wind blowing your mind away in it's direction. and yes it has a real impact on like your hormones and blood flow...hence you can gain more control over muscles.