1. One topic, one email
If you want to send a new email to someone, don't find an old one from them and reply to them with an unrelated item. Copy and paste their email address into a new email (if your address book doesn't automatically populate their info) and add a new subject line. This alerts them to the fact that a new issue has arisen, and also prevents old content from being shared with others who may need to be included on the new thread. Finally, you avoid "thread fatigue" in which the interest level of a recipient is inversely proportional to the number of entries in the thread. Intro email > response > final reply is much more effective than Intro email > response > reply > response > new topic > responses!
2. Write things down
It never ceases to amaze me that people will attentively listen to feedback, and walk away without having written any of it down. In a busy office environment, who has the mental capacity to remember important details despite the constant flow of cross-talk, meetings, context switches, and so on? Pretty much no one. Do yourself a favor and get a notepad you can comfortably carry, and a nice pen that you enjoy holding, and start writing stuff down. You can always convert the info into notes later -- having the ability to jot down notes and questions at any time will make a big difference in your ability to be accurate and complete in your work.
3. Ask questions
When talking with team members about a topic, don't just smile and nod when unfamiliar terms are presented. Instead, find a good time to ask what they mean. If you don't have an opportunity to ask at the time, write the issue down as a follow-up item on your handy notepad (see above) and pursue the answer later. It may feel a bit uncomfortable at first, because you are letting your team members know you don't know absolutely everything...but hey -- realistically no one can know everything. By asking questions you improve your ability to do a good job. Take the plunge and get the data you need to do a better job.