no articles | gender | plurals | negation | declination | grading | tenses |

There are no articles before nouns - if there is a zero article the noun has the same meaning as if there was a/an before it. If there is "ten, ta, to" before the noun, it has a definite meaning.
noga = a leg
ta noga = the (this) leg
There is a grammatical gender - three types: masculine, feminine and neuter. Every noun has its gender which is mostly signified by its ending, but of course there are exceptions.
MASCULINE: (ends predominantly in a consonant)
człowiek = human, person, man
syn = son
pies = dog
stół = table
samochód = car
Kraków = Cracow
FEMININE: (ends predominantly in "a")
mama = mom
kobieta = woman
żyrafa = giraffe
rodzina = family
książka = book
Warszawa = Warsaw
wiosna = spring (the season of the year)
NEUTER: (ends predominantly in "o" or "e")
dziecko = child
miasto = town
morze = sea
Zakopane = Zakopane (a town in the mountains)

There are exceptions - just to give a few examples:
Masculine Exceptions: kierowca (driver), myśliwy (hunter)
Feminine Exceptions: wieś (village), Bydgoszcz (a large Polish city)
Neuter Exceptions: centrum (centre)
Plurals can be in the most extreme cases difficult even for native speakers. To describe them (and the conjugation system) is beyond the scope of this outline. Some rules are pretty easy, some are less easy. As an example: ludzie, synowie, psy, stoły, samochody; mamy, kobiety, żyrafy, kierowcy, rodziny, książki, wiosny; dzieci, miasta, morza; myśliwi, centra.
You negate by adding "nie" before verbs.
Mogę (I can) - Nie mogę (I can’t)
Idzie (he goes) - Nie idzie (he doesn't go/ he is not going)
If an object is negated it becomes genitive instead of accusative (just for your reference - this can already be too difficult) Mam dom (I have a house) - Nie mam domu (I don't have a house)
There are 7 cases and each of them can have a different ending. If we take into consideration the fact that there is a plural and singular number, there can theoretically be up to 14 grammatical endings in case of one single word. In fact, this never happens as some endings are the same and the job becomes easier by placing a given word in several noun categories that are characterized by the same endings.

KOBIETA (feminine) - a woman
1. nominative KOBIETA (subject)
2. genitive KOBIETY (e.g. of woman)
3. dative KOBIECIE (e.g. to/for woman)
4. accusative KOBIETĘ (object)
5. instrumental KOBIETĄ (e.g. with woman)
6. locative KOBIECIE (e.g. about woman)
7. vocative KOBIETO!

and plural

As you can see in singular dative or locative, there are irregularities like a change of the stem consonants. Some cases are used with prepositions.
The second grade is formed by adding a suffix "-(i)ększy" or "-(i)ejszy" or just "-szy". The superlative is formed by adding a prefix "naj- " to the second grade.
Ładny - beautiful
Ładniejszy - more beautiful
Najładniejszy - (the) most beautiful
There are no perfect tenses. There are just three tenses: future, present and past. A special category - a prefix or a suffix can decide if the state or action was (or will be) finished or unfinished.
robię - I make (I am making)
robiłem - I used to make
zrobiłem - I made
będę robił - I will be making
zrobię - I will make