Learn Hardcore German: Ihr Blick war komisch, doch sie blieb freundlich. - Her look was odd, yet she remained friendly.

Because the second clause has sie blieb with a singular verb (blieb), sie must be she. That makes sentence-initial Ihr = her (her look/gaze). The capital I does not prove it’s formal your; it’s capitalized simply because it’s the first word of the sentence. Outside sentence-initial position, Ihr (capital I) would be formal your; ihr (lowercase) can be her/their depending on context.

Why is it ihr Blick and not ihren Blick?

Blick is the subject and is in the nominative case, so the possessive determiner stays uninflected in masculine nominative: ihr Blick. You’d use ihren Blick for masculine accusative: Ich sah ihren Blick. Quick patterns:

Masculine nom: ihr Blick
Masculine acc: ihren Blick
Feminine nom/acc: ihre Hand
Neuter nom/acc: ihr Kind
Plural nom/acc: ihre Augen

What exactly does Blick mean here?

Blick is the look/gaze, often the look in someone’s eyes. It’s less about the whole face and more about the eyes/direction of looking. If you want the full facial expression, say Gesichtsausdruck: Ihr Gesichtsausdruck war …

Does komisch mean funny or strange?

In everyday German, komisch most often means strange/odd/peculiar. For funny/amusing, prefer lustig or witzig. If you want to avoid ambiguity, use seltsam or merkwürdig for strange.

What does doch do here? Can I just use aber?

Here doch is a coordinating conjunction meaning but/however, often with a slightly stronger concessive feel (but despite that). You can replace it with aber with no change in word order: Ihr Blick war komisch, aber sie blieb freundlich. Aber is the most common neutral choice; doch can sound a bit more pointed or stylistically varied.

Can I use jedoch, dennoch, or trotzdem instead of doch? What happens to word order?

jedoch and dennoch are conjunctive adverbs; they trigger inversion (verb comes before the subject): Ihr Blick war komisch; jedoch blieb sie freundlich.
trotzdem is also an adverb and behaves the same: Ihr Blick war komisch; trotzdem blieb sie freundlich. With coordinating aber/doch, keep normal V2 order after the conjunction: …, aber/doch sie blieb …

Is the comma before doch required?

Yes. Doch (like aber/sondern) connects two main clauses, and German requires a comma before it: …, doch …

Can I say …, doch blieb sie freundlich.?

Not with doch as a coordinating conjunction. After coordinating doch, the next clause uses normal verb-second order with a subject (or another element) first: …, doch sie blieb freundlich. If you want inversion, use jedoch/dennoch/trotzdem: …, jedoch blieb sie freundlich.

Why blieb and not just war? What’s the nuance?

Bleiben + adjective means remain/stay + adjective. Sie blieb freundlich says she maintained friendliness despite something (the odd look). Sie war freundlich simply states she was friendly, without the idea of persistence.

What tense are war and blieb? Would the perfect be more natural in speech?

Both are preterite (simple past). In spoken German, the perfect is common for many verbs, so you’ll often hear Sie ist freundlich geblieben. For sein, the preterite war is very common in speech too; ist gewesen is possible but often avoided unless a specific aspect is needed.

Is freundlich an adjective or an adverb here?

It’s a predicative adjective after a copular verb (bleiben works like sein/werden). German doesn’t add a special adverb ending like English -ly; adjectives serve both roles: freundlich sein/bleiben = be/remain friendly.

Could I flip the clauses?

Yes: Sie blieb freundlich, doch ihr Blick war komisch. The meaning and grammar stay the same; keep the comma.

Could I express the same idea with obwohl?

Yes, but the structure changes because obwohl introduces a subordinate clause: Sie blieb freundlich, obwohl ihr Blick komisch war. (Subordinate clause sends the verb to the end.)

Any capitalization traps with Ihr/ihr and Sie/sie?

At sentence start, Ihr is capitalized anyway; context must disambiguate whether it’s her or formal your. Here, sie blieb (singular) shows it’s her.
Sie (capital S) elsewhere is formal you; sie (lowercase) can mean she or they. Agreement helps: sie blieb = she (singular), sie blieben = they (plural).

Are there better word choices than komisch or freundlich in some contexts?

For strange: seltsam, merkwürdig, eigenartig (clearer than komisch).
For friendly: höflich (polite), nett (nice), zuvorkommend (accommodating), depending on nuance. For customer-facing tone, freundlich bleiben is a very idiomatic collocation.