Help with Japanese saying things like "should" do that?

Question:

In Japanese how do you say things like, "you should talk to him" (of course pronoun inplied most of the time) Saying things like, "you shouldn't do that. I would not have done that, he wouldn't have, what should I do," and such. Then how would I connect these sentences (or do you not do that) like this one "He is a student studying Japanese, you should talk to him,(or he would like to talk to you)" how to you put two verbs in a sentence and put in conjunctions correctly.

Answer:

"you should talk to him" 彼と話してみたら？彼と話したほうがいいよ。

"you shouldn't do that. そういうことはしないほうがいいよ。(may sound critical)
それはやめたほうがいい。

I would not have done that, 私ならそうはしないかな。
"かな" in the end functions as a cushion for a torn down and avoid to sound too harsh or critical.
You often see this in question forms. But here, it sounds like "I guess you shouldn't be doing that."

he wouldn't have, 彼ならしないと思う。

what should I do,どうすればいいんだろう。(in lost)
どうすればいいと思いますか？(asking for a suggestion)

"He is a student studying Japanese, you should talk to him," 彼は日本語を勉強してるんだけど、(and) 彼と話してみたら？(suggestion) or 彼と話したほうがいいよ。(Surely this intrigues the other person's Why? Better go with the suggestion form though still may be asked for what reason...)

(or he would like to talk to you) 彼は日本語を勉強してるんだけど、(and) 彼があなたと話がしたいって。
"I have a father but do not have a mother"　(私には)父親はいますが(but)、母親はいません。

English auxiliary verbs do not always correspond with direct translations of its Japanese, so the best you could do is to learn them one by one in different context.