Sō iu toki wa, Kanda-san ni kiitara ii yo. In that case, you should ask Mr. Kanda.

Situation 1: Ms. Gray asks a coworker about some software.

グレイ: このソフト、もっといい使い方があると思うんだけど、どうしたらいいと思う?

三田: そういうときは、神田さんに聞いたらいいよ。すごく詳しいから。

Gurei: Kono sofuto, motto ii tsukaikata ga aru to omou-n da kedo, dō shitara ii to omou?

Mita: Sō iu toki wa, Kanda-san ni kiitara ii yo. Sugoku kuwashii kara.

Gray: I think there’s a better way to use this software, what way do you think is best?

Mita: When talking about such things, it’s better if you ask Mr. Kanda. Because he’s very detailed.

There are a few ways to go about asking for and giving advice in Japanese. One way is to use the expression, Xたらいいです(よ). In this case, “X” should be a verb in its suppositional tara-form, like the 聞(き)いたらいいよ (I suggest you ask) in Situation 1. This structure is used to present advice or a suggestion to your equal or junior. (Note: Giving advice to your superiors and elders can be perceived as impolite in Japanese, so this pattern shouldn’t be used in those cases.)

You can also change the verb in its tara-form to its ba-form — for example, 聞けば instead of 聞いたら — and convey a similar meaning. However, substituting “ね” for “よ” at the end of the expression changes the nuance and translates as “it’ll be good if X is realized.”: 神田(かんだ)さんに聞いたらいいね (It’d be great if [you] asked Mr. Kanda).

When Ms. Gray asks for advice in Situation 1, she can say either どうしたらいいですか or どうすればいいですか to similar effect:

A: 予約(よやく)をキャンセルしたいんですけど、どうしたらいいですか? (I’d like to cancel my reservation. What should I do?)

B: ホームページから自分(じぶん)の予約番号(ばんごう)を入(い)れて、キャンセルのボタンをクリックすればいいですよ。

(From the homepage, you should input your reservation number and push the cancel button.)

Situation 2: Mitsuo talks to his mother about dinner.

光男: 今晩は豚の生姜焼きじゃなくて、ラーメンが食べたいなあ。

母: そんなにラーメンが食べたいなら、自分で作れば?

Mitsuo: Konban wa buta no shōgayaki janakute , rāmen ga tabetai nā.

Haha: Sonna ni rāmen ga tabetai nara, jibun de tsukureba?

Mitsuo: This evening, instead of ginger pork, I’d love to eat some ramen.

Mother: If you want to eat ramen that much, why don’t you make it yourself?

To make Xたらいいです(よ) and Xばいいです(よ) more casual, drop the いいです(よ) and say the word with rising intonation:

A: 函館(はこだて)に行(い)くんだけど、どこがおすすめ? (I’m going to Hakodate, where do you recommend [going]?)

B: うーん、函館山(はこだてやま)に行って、夜景(やけい)を見(み)たら? (Well, I recommend going to Mount Hakodate, to maybe see the night views?)

It’s worth noting that this type of casual structure is often used to express a cold or disapproving attitude toward the listener, which is what Mitsuo’s mother is doing in Situation 2. However, it just depends on context.

Bonus Dialogue:
Mariko asks her mother to take her to Disneyland. Her elder siblings, Mitsuo and Takako, join in the conversation.

まり子(こ): ねえ、みかちゃんはディズニーランドに行ったんだって。それで、新しくできたアトラクションに乗 (の)ったらいいよ、って言(い)ってたよ。ねえ、うちもディズニーランドに行こうよ。

母(はは): そのうちにね。

まり子: そのうちって、いつ?すぐ行きたいよ。

光男(みつお): それは、うちの経済事情(けいざいじじょう)によるよ。まり子が一人(ひとり)で行けば?

たか子: そんないじわる言っちゃだめだよ。

まり子: みんなで一緒(いっしょ)に行こうよ。ねえ、どうしたらいいの?

光男: そうだなあ… お母(かあ)さんのお手伝(てつだ)いをたくさんして、いい子でいればいいよ。

たか子: まり子は、だいたいいい子でいるよ。それは、お兄(にい)ちゃんがいつも言われてることでしょう?

光男: うーん、それはその通(とお)りだ。

まり子: じゃあ、次(つぎ)の冬休(ふゆやす)みにみんなで行こう!

Mariko: Hey, I heard that Mika went to Disneyland. And then, she told me I should try ride the new attraction (they have). Hey, let’s go to Disneyland, too!

Mother: Someday.

Mariko: Someday, when? I want to go there soon.

Mitsuo: It depends on our economic situation. Mariko, why don’t you go by yourself?

Takako: Don’t say such mean things.

Mariko: Let’s everyone go together. How can we do that?

Mitsuo: Hmm, let’s see… what if you help Mom a lot and be a good girl?

Takako: Mariko is usually a good girl. Isn’t that what you’re always saying, big brother?

Mitsuo: Yeah, I say exactly that.

Mariko: OK, let’s go next winter vacation!