Learn Hardcore Russian: Я поблагодарил её и сказал, что такая похвала помогает мне работать увереннее. - I thanked her and said that such praise helps me work more confidently.

Поблагодарил is the perfective past tense, meaning a completed, one-time action: “I thanked her (once / at that moment).”
Благодарил is imperfective and would suggest a process, repetition, or background action, e.g. “I was thanking her” / “I used to thank her.”

What does the по- in поблагодарил add?

In this verb it’s part of making the verb perfective: благодарить (impf.) → поблагодарить (pf.).
Here it signals “to thank (and be done with it),” not “to thank a bit” in a literal sense.

Why is её used, and what case is it?

Её is the pronoun она (“she/her”) in the accusative case, used as the direct object of поблагодарил: “I thanked her.”
(For an animate female noun/pronoun, accusative looks like genitive: она → её.)

Can I change the word order to Я её поблагодарил? Does it change the meaning?

Yes, both are grammatical:

Я поблагодарил её is neutral.
Я её поблагодарил is also common; placing её earlier can slightly increase focus on “her” (often depending on context/intonation), but the basic meaning stays the same.

Why is there a comma before и: Я поблагодарил её и сказал, что…?

There’s no comma between её and и сказал because поблагодарил and сказал share the same subject я and are joined by и.
But there is a comma before что because что такая похвала… is a subordinate clause (reported speech/content clause).

What exactly is что doing here? Is it “that” or “what”?

Here что is the conjunction meaning “that”, introducing what was said:
“I said that such praise helps me…”
It’s not the pronoun “what” in this sentence.

Why is it такая похвала (feminine), and not такой/такое?

Because похвала is feminine singular, so такой/такая/такое must agree in gender and number:

такая похвала (feminine)
такой отзыв (masculine)
такое сообщение (neuter)

What case is похвала here, and why?

Похвала is nominative singular because it’s the subject of помогает:
(такая) похвала помогает… = “(such) praise helps…”

Why is мне used (dative), not меня?

Because помогать (“to help”) normally takes the person helped in the dative:

помогать кому? → мне (“to me”)
So: похвала помогает мне… = “praise helps me…”

Why is работать an infinitive after помогает?

Russian often uses помогать/помочь + infinitive to mean “help (someone) to do something”:

помогает мне работать = “helps me work” / “helps me to work”
You can also say помогает мне в работе (“helps me in my work”), but the infinitive version is very common.

What is увереннее grammatically, and why not уверенно?

Увереннее is the comparative form of the adverb уверенно:

уверенно = “confidently”
увереннее = “more confidently”
So работать увереннее means “to work more confidently.” A close alternative is работать более уверенно, which is a more explicit “more + adverb” structure.

What does the sentence literally mean word-for-word?

A fairly close mapping is:

Я = I
поблагодарил её = thanked her (completed action)
и сказал = and said
что = that
такая похвала = such praise
помогает мне = helps me
работать = to work
увереннее = more confidently