To understand how to use deductive reasoning, one must first understand the core philosophy behind it:
"When you have eliminated everything that isn't provable, whatever remains, even if it's unlikely, must be the solution."
The methods used to successfully make deductions is as follows:
Find a true statement
Find another shred of evidence
Relate them logically, but accurately
Note: I wouldn't try this until you've trained the skill
Examples of Deductions (I've Done These):
A woman who works at a bank appears in late 30s or mid-40s, hardly looks around, has a blank expression, a necklace, bracelet, and a wedding ring, nails clean and painted, glasses, and dark hair...what deductions can logically be made???
A middle-aged woman, likely 30s-40s, is a professional who works at a bank likely for most of her life and hopes to retire one day. She has clean appearance which means she pays attention to how she looks. Now the impressive deduction, her jewelry. All of it clean and shiny means she appreciates her life. A detailed look at her ring means she's been happily marries 7-12 years. This is true because the outside and inside of her ring are clean, which means she polishes it normally...a detailed and obvious clue that the only cleaning it gets ISN'T when she takes it off her finger. This further means that the woman has never been a serial adulter.
A man with an injury that appears as if it's present one moment and not present the next...Here's what this means:
A man has a psychosomatic injury which also means they have a therapist.
A man in his late 30s with his shirt collar stained with motor oil, hands calloused, left hand appearing more torn, and a visible, but slightly fading ring mark, visible...what could this mean???
The man is a mechanic in his 30s who is left handed and divorced likely for 2-3 years.
A 19 year old girl with blonde hair, professional looking images, social media, a recently ended relationship with a controlling boyfriend, figure of an athlete, speaks 3 languages, studying psychology, and is from Vienna...what could possibly be the deduction???
An emotionally damaged 19 year old girl likes drawing attention to herself, hinting from the blonde hair(also genetic), social media and brighter clothing. Since she can remember she was masking who she really was because she thought that it was best for her to be what other people thought of her. Hints why she studies psychology and language, so she can learn to understand other people and act as her true self around them but better. Based on her relationship outcome and type, she likely believes love = pain, which is why she wouldn't readily be with anyone for a while. Based on her place of residence, she speaks English, German, and knows some Spanish.
Observation Exercises & Steps:
Given a photo or description of a person, describe them by deducing unseen or unheard things
Observe...don't just see
Eliminate the impossible
Never theorize before you have all of the facts