Thank you for this great summary. I could not agree more.

1: Providing training and reference material to the linguistic team before starting translation educates the linguistic team about the content they will be localizing, resulting in better quality translations.

This is indeed essential... but unfortunately happens rarely in my experience. Typically, I have had to find reference materials myself as a translator or editor. There have been even cases when I was provided with Workbench RTF files created from MIFs, but for some reason could not obtain the respective PDF files for reference.

3: If the customer is satisfied with the quality of previous or current projects, requesting that the same team of linguists be used across all projects will help ensure consistency and quality. (For example, this could mean that the same linguists should be used on all projects whether they are software, help or documentation.)

Absolutely. In my experience, the consistency can drop by as much as 50% when the team of linguists is changed. Because translation is inherently subjective and largely depends on individual translator's preferences, new translators often edit the existing translations heavily to make them look more like their own. I have seen only few translators who were disciplined enough to adhere to TM consistently and refrain from editing 100% and high-percentage fuzzy matches.

4: Creating and maintaining project glossaries helps to ensure consistent terminology across projects. It is also helpful if the glossaries contain definitions to help linguists better understand the meaning of each term.

Project glossaries are certainly an excellent way to maintain consistency. Aside from just requesting a translator to use them, it is important to also use them in a terminology checker such as QA Distiller in each job to make sure that the translator strictly followed a glossary. With long-term jobs, the glossary might grow to thousands of words, so this terminology check consumes much time in each job, but in the end of the day this effort is certainly worthwhile.