How to pronounce English words in Chinese
There are two directions you mentioned:


transliteration or romanisation using Wade-Giles (Tao for 道) or Pinyin (Dao for 道) to write/spell/pronounce chinese characters/words (see Taoism VS Daoism). This facilitates the usage of Chinese words in English language (e.g. Beijing).
loan words or using English words in Chinese language


You are asking for the latter.

How to choose characters?

For the selection of matching chinese characters  there is always the trade-off between phonetic (sound) as well as semantic (meaning) similarity.

Some are just resembling phonetic:
For example 打的 (dadi) means (to go by) taxi. It's colloquial although there are "original" chinese idioms for that, e.g. 出租车 (chuzuche) meaning taxi (or rental-car in Taiwanese).

Difficult to reflect both, sound and meaning:
Especially foreign businesses are smartly applying creativity to give there brands recognizable chinese names (easy to associate and remember).

That effort leads for example to IKEA translated to 宜家 (yijia) literally proper-home, or Cola to 可乐 (kele) literally amusing/entertaining.

Localised Foreign Brand Names

Since you are asking especially for the "translation" of brand names, there are further aspects for selecting the right characters/words:


cultural fit
socioeconomic and psychological associations
historical and traditional reflections


Above factors are essential for designing brands, not only for translating their names.

The difficulty in selecting a suitable chinese brand name may even include visual (stylish) aspects: aesthetic and beauty of the characters, since they should appeal visually to the target audience:


  The translation from English brand to Chinese brand involves issues of “translating a name from a letters -and- phonemes-based phonographic language (i.e. English) to a visual-character-based logographic language (i.e. Chinese)”  (Schmitt &amp; Zhang, 2012, p.656).


Refer to examples where the name was selected to incorporate such aspects, although neither matching phonetically nor semantically:


Poison (a luxury fragrance) was retranslated to 百爱神 (Bai Ai Shen), which means everyone will love it. So that people would like to purchase it, rather than they would if it has a negative connotation like its original name and meaning.


Further Reading

Branding in China is covered by many Studies and Research Papers, published at Universities by sinologists and economists alike:


Shi, H. (2017). Translation Strategies from Target Culture Perspective: An Analysis of English and Chinese Brands Names.  International Journal of English Language &amp; Translation Studies. 5 (1), 15-22.
Berende, B. (2012) : What’s in a Name?  A study on the success factors of brand naming in China. Master Thesis, Jönköping International Business School