Though all of these phrases have a common theme, their grammar and usages do vary significantly. So, please be sure to not rush through them even if you've seen them show up many times in your studies thus far.
様 is a noun that literally means "appearance". ～ようだ is a 形容動詞 conjugating ending that comes from it, and it has many applications.
～ようだ
Overall, ～ようだ is like "like" or "seem". よう is a noun itself, so when used after nouns, precede it with の. When after 形容動詞, use な!
1. 僕の犬は言葉が分かるようだよ。
My dog seems to understand words!
2. 爬虫類のようで、実は、哺乳類だ。
It looks like a reptile but in reality is a mammal.
漢字 Note: 爬 and 哺 are rare. So, you don't need to worry about them.
3. すこし塩辛いようですね。
It's kind of salty, don't you think?
Word Note: 辛い is often used to mean "salty" in West Japan. The word 塩っぱい also exists. In this word, 塩 is pronounced as しょ.
4. どうも壊れているようだ。
Presumably, it's broken.
5. みな元気なようです。
Everyone seems fine.
6. 彼はとても悲しんでいるようです。
He seems to be very sad.
7.何か隠しているようです。
He appears to be hiding something.
8. あの人を見たような気がしました。
I felt like I saw that person before.
9. ちょっと怒ったように聞こえた。
I heard her like she was a little angry.
10. ステーキかまたはそれと同じようなものを食べる。
To eat steak or something just like it.
11. 彼は、何も言いたくないような、押し黙った表情をしてる。
He's reticent as if he doesn't want to say anything.
12. 彼は、何も言いたくないようで、ぶすっとしてる。
He's in a bad mood not saying anything.
13. 難しかったようです。
It looks like it was difficult.
14. 対策もなく、俎板の鯉のようなものだ。(Idiomatic)
It's basically a hopeless situation without a countermeasure.
まるで & ～かのようだ
～ようだ is also often paired with まるで to make "just like", and when used with the particle か, it creates "as if".
15. マイクさんはまるで天使のような人ですね。
Isn't Mike just like an angel?
16. まるで人でも殺したかのように、ぼうぜんとしてる。
He's dumbfounded as if he's killed a person.
17. 彼の病気はまるで神様が治してくれたかのようにきれいに消えましたよ。
His sickness disappeared as if it was by God.
18. 地に膝をつくかのように木が風に揺れていた。
The trees swayed in the wind as if they knelled to the ground.
～よう｛なら・だったら｝
～よう｛なら・だったら｝ euphemizes a supposition.
19. この治療｛手当て・処置｝で治らないようだったら病院に行ってくださいね。
If you don't get better with this medical treatment, please go to the hospital, OK?
～ようになる
～ようになる shows that a state changes. It indicates a state that could not be done has become one that can be done. It can also be used in the negative. Also, ～ないようになる can be contracted to ～なくなる. The pattern can also be used to show acquisition of a habit or custom.
20. 六年ぶりに旧友と会えるようになった。
After six years I was able to meet an old friend.
21. 日本語で挨拶ができるようになりましたよ。
I have become able to greet in Japanese.
22. 「日本語の勉強はどうですか」「宿題が簡単にできるようになりましたし、それに日本人と毎日会話をしてい ます」
"How are you Japanese studies?” “Homework has become easier to do, and furthermore, I converse with Japanese people every day".
23. 最近、彼女はよく話すようになりました。
She recently started to talk a lot.
24. 彼はテレビを見なくなりました。
He stopped watching TV.
The Noun よう
The noun よう may be after the 連用形 of verbs to show appearance or method. It can also function as a nominalizer.
25. 言おう様ない (Rare) ＝ 言い様のない
Indescribable
26. その苦しみようは見ていられない。
I can't stand watching that miserable condition (of that man).
～みたいだ is for the most part a more casual variant of よう for comparison, but since it does come from 見る (to see), it shows that something "resembles...". It acts as a 形容動詞. So, you can see ～みたいな (adjectival) and ～みたいに (adverbial). The negative should be ～ないみたいだ. but in slang you may still see ～みたくない.
27. 兄は侍みたいな人だね。
My older brother is like a samurai.
28. 真っ暗で雨が降ったみたいだ。
It was like rain had fallen in pitch black.
29. ガムみたいに伸びるものだ。
It's a thing that stretches like gum.
30. もう売り切れみたい。
It looks like it's already sold out.
31. 誰もいないみたいだが。
It seems that nobody is here, but...
32. 夢みたいな話だ。
That's a story resembling a dream.
33. 壁は紙みたいに薄いよ。
The walls are thin like paper.
34. 味がすこし薄いみたいです。
The taste seems to slightly be weak.
Origin Note: ～みたい comes from ～みた様, which can still be seen in literature.
The 形容詞 conjugating suffix ～っぽい is often discarded as slang. However, it is becoming very popular. It is very similar to "-ish". After the stems of adjectives, it shows a distinct nature. With nouns, it shows a strong impression about what something is like. However, when attached to the 連用形 of verbs, it shows tendency. Now it can be seen after the 終止形 to mean "looks like".
35. 彼女は全然女っぽくないな。
She's not womanly at all!
36. 君の欠点は忘れっぽいことだぞ。(Masculine)
Your fault is that you're forgetful.
37. なんて嘘っぽい話や！ (関西弁)
What a lie!
38. 埃っぽい
Dusty
39. 最近忘れっぽくなった。
I tended to forget the recent times.
40. 荒っぽい行動。
Rough conduct.
41. 彼は熱っぽく身が震えていた。
His body was feverishly shaking.
42. この酒は水っぽいの。(Feminine)
This sake is watery.
43. 理屈っぽい
Argumentative
44. マジで安っぽいテレビだな。 (Casual)
It's really a cheap TV, isn't it?
45. やるっぽい！ (Casual)
It looks like he's doing it!
46. 病院っぽい雰囲気
A hospital-like atmosphere.
47. 子供っぽいことすんなよ。 (Masculine)
Don't do something childish.
48. バナナっぽい香りが好きだわ。(女性言葉)
I like banana-like fragrances.
49. 黒っぽい車でした。
It was a blackish car.
50a. 哀れっぽい声
50b. 哀れめいた声 （More serious)
A piteous voice