Avoid slangs, number substitutions and technical jargons
Slangs are normally limited to a particular locality or place. Moreover, it is not as impressive as a real word. Similarly, replacing words like "for" and "to" with numerals "4" and "2" can be quite confusing and lead the visitors to wrong sites. Also, when you add jargons related to your website topic, though jargon names are easy to get, make sure they are common enough for all visitors to understand and remember.