Learn Hardcore Russian: Новая грамматическая тема: конструкция «лучше бы» выражает совет, пожелание или сожаление. - New grammar topic: the construction “лучше бы” expresses advice, a wish, or regret.

Breakdown of Новая грамматическая тема: конструкция «лучше бы» выражает совет, пожелание или сожаление.

What is the closest English equivalent of лучше бы?

It depends on context, but the closest English equivalents are often:

Examples:

Лучше бы ты пришёл раньше.
= It would have been better if you had come earlier / You should have come earlier
Лучше бы он позвонил.
= I wish he would call / It would be better if he called

So лучше бы is broader than any one English phrase.

Why is the particle бы used here?

Бы adds a hypothetical, non-factual, or desirable meaning.

Compare:

So бы is what makes the phrase sound like a suggestion, wish, or regret rather than just a plain comparison.

For example:

Это лучше. = This is better.
Лучше бы ты ушёл. = It would be better if you left / You’d better leave

What verb form usually comes after ?