Opening a discussion

To begin with,

We need to discuss . . .

determine
find out

Let's start by (V ing)

We'll start by (V ing)

The problem here is . . .

issue
question

The important thing (here) is . . .

The main thing we need to discuss is . . .

Let's look at . . .

It looks like . . .

It appears that . . .

Asking for input
What do you think?

How about you?

How do you feel about that?

Any ideas on that?

Responding

(That sounds like a) good idea.

Sounds good.

The problem with that is . . .

That raises the issue of . . .

brings up