那是做事的一特樣 doesn't make sense. There isn't the word "特樣“ in Chinese. I didn't understand what you meant by that until I saw its English version. I'd say 那是一种特别的做事方法。

The first sentence is probably wrong;) The correct translation can be: 那是做事的一种特殊方法。 "样“ means shape or outlook in most situation. But also pay attention, it's not quite right to say "特方法”, "特殊“ is always better since it's a full adjective. - I can't understand the second doubt clearly, could you give me an example?

To answer your second question, you don't put the adjective between the number and the "measure" word. You put the adjective after the "measure" word. The correct way to phrase it is "今天我喝了一杯很爽口的可口可樂" (爽口 means tasty)