1. 쇼핑 업체는 실제 나이보다는 체감 나이에 초점을 맞출 필요성이 있다
=> There is a need for retailers to FOCUS ON felt age rather than biological age of shoppers.
2. 쇼핑 업체는 실제 나이보다는 체감 나이에 집중할 필요성이 있다
=> Retailers would do well to CONCENTRATE ON felt age rather than biological age of shoppers.
(체감 = feeling with your body/senses. Naturally felt; 초점 = focal point. 초점을 맞추다 = to focus)
Both are fine, but #1 seems better. 집중하다 suggests an intense activity which doesn't fit the sense of changing the focus or direction in this sentence.
1. 출근 시간을 달리한다면 업무의 효율을 향상시킬 수 있다.(If you change the starting hours, you would be able to increase productivity) - NATURAL.
2. 출근 시간을 달리한다면 업무의 효율을 향상할 수 있다. NOT AS CLEAR
향상하다(to improve/increase) here has a clear sense of affecting something else (i.e. transitive), and therefore sounds more natural with the -시키다 ending. 향상하다 is sometimes used as an intransitive verb but it's rare and does not fit this example well.
Some hanja-based words work equally well with multiple endings such as -하다(default), -시키다(causative), and -되다/당하다(passive) endings (e.g. 확립하다, 확립시키다, 확립되다) while others are used mostly with only one (헌신하다 is common, 헌신시키다 rare, and 헌신되다 nonexistent). Unfortunately, there is no simple way to know which verbs follow which of these usage patterns (it's related to the verb's exact meaning and connotation), so you'll just have to note it as you encounter new verbs.