As a native English speaker, something I really struggled to grasp when learning Polish was the grammar, in particular the 7 cases. I read many texts but it was difficult to take and far more difficult to remember so I devied the below flow chart -

Polish Grammar in Tablular Form

		Masculine			Neutuer		Femenine
		Animate	In-Animate	Plurarl	Singular	Plurarl	Singular	Plurarl
Nominative	Nouns			Add 'e' - (-ć, -dź, -ś, -ń, -ź) as well as with -c, -dz, -cz, -dż, -sz, -ż, -rz, -l, -j. Add 'i' - ł, -m, -r, -b, -d, -w, -z, -ch, -s, -p, -t and many more. In this case softening of consonants occur: z -> ź, d -> dz, t -> c und ch -> s. Add 'y' –k, -g, -or, -ec, -er, but not only them. In this case k to c, g to dz and r to rzchange occur.		Swap last letter for 'a'		Swap last letter for 'y' or 'i'
	Adjectives	y			e		a
Genetive	Noun	Add 'a'	Add 'u'	Add 'ow' Add 'i' - with -ąb and -w Consonants Softened	Last letter becomes 'a'	Drop last letter	'a' becomes 'y'	Drop last letter
		Consonants Softened		with -ąb and -w ending get in the genitive plural -i suffix. Consonants Softened			–ka, -ga or consonants like –ć and -ź, –y ending replaced by –i. In these cases letters –ć and -ź are removed and replaced with “normal” consonants.
	Adjectives	ego		ych/ich	ego	ych/ich	ej	ych/ich
Dative	Noun	owi		Swap last letter with 'om'	Swap last letter with 'u'	Swap last letter with 'om'	–(i)e ending with consonant or of foreign origin –y/-i	Swap last letter with 'om'
		Consonants Softened
	Adjective	emu		ym	emu	ym	ej	ym
Accusative	Noun	Nominative PL	Genetive PL		Nominative		'a' becomes 'ę'	Nominative PL
	Adjectives	Genetive	Nominative				Swap last letter with 'ą'
Instrumental	Noun	Remove '-ie', Add 'em' Add 'iem' - ends with -g or -k Consonants Softened		'ami'	Add 'm'. If ending in o replace with 'em'	'ami'	'ą'	'ami'
	Adjective	'ym' -im (after -g or -k)		'ymi' -imi (after -g or -k)	'ym' -im (after -g or -k)	'ymi' -imi (after -g or -k)	'ą'	'ymi' -imi (after -g or -k)
Locative	Noun	'e'/'u' Consonants Softened		'ach'	'e'/'u'	'ach'	Dative	'ach'
	Adjective	ym/im		-ych/-ich	'ej'	-ych/-ich	-ej	-ych/-ich

Genitive
Often used with interrogative pronouns, where questions czyj?/czyja? are asked, being close to the English question “whose?” and its usage of genitive

• To specify who is the owner of something or what something belongs to
• In sentences with certain verbs, expressing negation, as well in sentences describing defect, absence or increase of something.
• With specified and unspecified quantity
• A few prepositions that require the genitive: niedaleko (near), bez (without), dla (for), do (to, into), koło/obok (near, by), podczas (during), wzdłuż (along), z/ze (from).
• In many sentences describing the specific time
• After a number used with a noun.

Dative
The target objects of specific activity.

Accusative (biernik)
It is related to the activity or function relative to the described object. It can be used as a single or prepositional case. The accusative answers to the questions kogo? (who?), co? (what?).

• Object indication in affirmative sentence
• With some prepositions like przez (through/over), po (in the German language used with the verb abholen or “pick up” ), na

Instrumental
Refers to the object of a sentence, never to its subject. The means by which an action is completed (eg go by taxi). used after z (with), za (behind). Also with nationality of profession.

Locative
Used after w (in), o (about), na (on), o (at), po (after,along), przy (near, by)

Consonants Softening

• to–ce
• -ga/-da to –dze
• -ta to –cie
• -ł to –l
• -ka to -ce
• -p to –pi
• -m to -mi
• -n to -ni

One of my biggest inspirations was this site - Mowic Po Polsku