Now that we are all here, let's begin the talk, shall we?
现在人都到了，咱们开始，怎么样？
What do you think if we begin now?
我们现在开始，好吗？
If you don't mind, I think we'd better begin right away.
你要是不介意，我们就开始吧。
Suppose we get down to business now?
现在我们开始怎么样？
Let's get straight down to business now?
我们直截了当谈问题吧。

Well, I know you're all extremely busy, so why don't we get started?
我知道你们都特别忙，那就赶紧开始吧。
As we are familiar with each other, let's come straight to the point.
大家都是熟人，我们就开门见山吧。
We've gone too far off the point. Let's return to the topic under discussion.
咱们离题太远了，还是回到正题上来吧。
Let's have a word about delivery, OK?
咱们谈谈交货问题，好吗？
Let's have a talk over the question of payment terms, if you don't mind.
你要是不反对，我们就谈谈付款条件。

Speaking of mode of payment, can you advise me of your general practice in this respect?
谈到付款方式，能否告诉我，你们这方面通常怎么做？

单词词组解析：

right away: 立刻
get down to: 开始认真考虑。在本文的句子中是指立刻开始讨论吧。还可以加入一些其他的形容词，比如：get straight down to. 更突出了直截了当的意思。
off the point: 离题，跑题。
delivery: 递送，交送，交货。在贸易交流中，这个词的意思是交货。
payment terms: 付款方式。在商务合同中还有很多其他条款，比如：检验条款，包装条款等等。