Follow up email in Japanese?

How do you write a follow up email to the person in regards to a topic?...

How do you usually start the email (if it is in polite form)?

Follow-up, as in, following up/thanking them for a face-to-face meeting you've had a few hours/few days ago, or simply another e-mail after an earlier one to provide additional information? Business? School? To your senior? customer? More context will be helpful in giving you more useful suggestions :)

Hi AK,

It is just another e-mail after an earlier one to obtain more information from the seller...



Thanks. :D

Oh, OK. I assume it's for a shop or an auction?


Re: (Be sure to put the item name or auction ID number)

Konnichiwa. (hello)
OR
Osewa ni natte orimasu. (a fixed greeting message often used in business.)

Sakihodo (...) ni tsuite goshitsumon shita mono desu. (I am the one who asked you questions earlier concerning (...))

OR - choose between these two depending on your e-mail exchanges so far.

Sakihodo wa (...) ni tsuite no gokaitou arigatou gozaimashita. (Thank you very much for your response earlier concerning (...).) - In case you've received an answer already.

Ikutsuka tsuika de okikishitai koto ga arimasu. (I have several more questions that I would like to ask.)

Thanks for the help AK.

If I want to say "Do you have {something} available?"

Is it like

{something} ga arimasu ga?

Is there a polite form for such question?

Do you have [something] available?
Your sentence is fine as polite form.

If I go a bit more respectful, as I've done with the sentences above, it will be something like:
(Do you have [something]? If you do, would you be willing to sell it?)
[something] wa omochi desu ka. Moshi omochi deshitara, utte itadakemasen ka.

In simple polite form, it would be:
[something] wa arimasu ka. Moshi areba, utte moraemasu ka.

Thanks for the explanations AK :)