Having recently been asked by a new client to do a mail out for over 11,000 emails, we thought that I would take a moment to do a write up and explain what I think are some of the important points and considerations in maintaining and operating large emailing lists. These are of course, legitimate, opt-in email lists, not those obtained by illicit means and for which you are essentially adding to the SPAM problem that already exists online. So here are 10 points for an effective email marketing campaign:

Use a Proper Email Service Provider
Use a proper email service provider to send and track your email campaigns. I have friends who recommend Campaign Monitor, but I know Aquarius Records, my favorite music store, uses List Box. Campaign Monitor might be costly if you are sending out emails on a regular basis, but there are masses of options out there, andwith some basic research you can easily come up with a provider that is right for you. The more you send, the more economical it becomes to find a service providing a flat monthly fee.

HTML Emails
Thanks to the newer generation of email clients and the explosion of webmail clients, the most reliable way to code HTML emails is similar to how we coded web sites in the 90s. Complicated layouts should use tables for layout, and you must use inline CSS to control fonts, colors. Try to code outside of the email application and import or copy and paste your HTML email into the app or service you are using. You can find a lot more info at Campaign Monitor Resources, Mail Chimp Resources, and Sitepoint Email Newsletters & related articles.

Optimize Images
When building HTML emails ensure that you optimize your images as much as possible without making them look bad and lossy. You should attempt to reduce the size of emails using every bit of equipment in your arsenal as possible. We no longer live in the age of mass 56K connections but you would still be best advised to keep bandwidth use to a minimum.

Don't Use Your Desktop Client
Whatever you do, don't use your own desktop client to send out mass emails. Piggy-backing off the such services is generally bad and can easily end up with you having your account terminated, in breach of terms of use. Such providers will do everything in their powers to make sure their range of IP addresses and mail server are always whitelisted, trusted by ISPs and staying off blacklists, grey lists and any other kind of list. To this end I would stay away from self-hosted apps such as PHPlist or other such web apps.

Get Setup Properly
Following the instructions offered by your email service provider to ensure that you are properly setup for any or all of DNS, SPF, Sender IDs and Domain Keys/DKIM. Without these you are automatically disadvantaging your email list, with the net result that more, if not all of them might be automatically junked by massive webmail service providers such as Hotmail, Yahoo and AOL.

Drip Campaigns
For sales-related campaigns consider performing Drip Campaigns. For those of you not use to this terminology, Drips are essentially the kind fo persistent and on-going campaigns pushing your wares, day-in-day-out to interested parties. Drip campaigns you may have seen or come across include those run by Amazon, Apple, eBuyer and other such online retailers.

Plain Text Versions
In short, always provide a plain-text version, or alternate content version to your emails. Either provide this as an option to users when they subscribe, to limit the size of emails and amount of bandwidth consumed, both at your end and theirs, or send out multi-part emails, in case the email client at the recipient's end is unable to handle your HTML.

Mobile Versions
In 2018, the number smart mobile devices means that many more people are checking emails from mobile devices rather than purely desktop or laptop computers with large screens, so you have to bear this in mind when pumping out emails to your users. If you can gather this information when registering users, so as to be able to optimize the format of your emails for their likely scenario, then that is the best of all possible worlds. in the absence of any remote access information, subscribe to the KISS philosophy (keep it simple stupid) and / or send plain text.

Don't Manually Manage Your List
Never manage your lists by hand. Managing lists by hand can quickly turn into a nightmare. List management is another reason to use a hosted service to send out your campaigns. By law you have to let people opt-out from your list and make sure they stay opted out unless they want back in.

Don't Bother Buying Lists
Do not buy email lists and blast them. ROI is VERY limited compared to lists you grow organically and nurture. Targeted marketing at people who are interested in your products, services or information is always best and produces much higher conversion rates. In addition, given that users will let their feelings be known by marking your emails and domains as spam, you are only shooting yourself in the foot in the long run. Email providers are not stupid and they do listen to the collective sigh of their users when they mark emails as junk mail.