Substituting certain words from your vocabulary can help your communication be crisper and make you sound more eloquent by getting to the point quickly without sounding unnecessarily verbose. Mentioned below are 50 such commonly used phrases/sentences and their substitutes.

1. a number of: some, many
2. afford an opportunity: allow, let
3. an appreciable number of: many
4. as a means of: to
5. as prescribed by: in, under
6. at the present time: now
7. by means of: by, with
8. comply with: follow
9. due to the fact that: because, due to, since
10. during the period of: during
11. for a period of: for
12. has a requirement for: needs, requires
13. have an adverse effect on: hurt, set back
14. in a timely manner: on time, promptly
15. in accordance with: by, following, per, under
16. in addition: also, besides, too
17. in an effort to: to
18. in close proximity: near
19. in lieu of: instead of
20. in order for: for
21. in order that: so
22. in order to: to
23. in regard to: about, concerning, on
24. in relation to: about, to, with
25. in the amount of: amounting to, for
26. in the event of: if
27. in the near future: shortly, soon
28. in the process of: (omit without replacement)
29. in view of: because, since
30. is applicable to: applies to
31. is authorized to: can, may
32. is in consonance with: agrees with follows
33. is responsible for: handles
34. it is essential that [one]: [one] must
35. it is incumbent upon [one] to: [one] should, [one] must
36. it is requested that you: please
37. pertaining to: about, of, on
38. provide(s) guidance for/to: guides
39. relative to: about, on
40. set forth in: in
41. similar to: like
42. successfully accomplish/complete: accomplish/complete
43. take action to: (omit without replacement)
44. the month (or year) of: (omit without replacement)
45. the use of: (omit without replacement)
46. time period: period, time
47. under the provisions of: under
48. until such time as: until
49. with reference to: about
50. with the exception of: except 

The list above simple alternatives to certain phrases and sentences that might be too complex for your audience. However, one can choose to use the relatively complex option depending on the type of audience you are catering to. Observe how often you tend to use these complicated phrases and practice replacing them