Its very important to use effective words during presentation and emails. There are few words which are to be avoided and here are words with the replacements-

Firstly
Use “to begin with” or “at first” to introduce the first of several points.
“such a fate is unlikely to befall him: to begin with, his is a genuine talent”

Secondly
use “in addition to” to introduce a second point or reason
“he was presented first of all as a hopelessly unqualified candidate and secondly as an extremist”

Thirdly
use “furthermore” used to introduce a third point or reason
“secondly, the Home Secretary has found a way to deal with the problem swiftly; thirdly, the Bill has received all-party support”

Lastly
use “at the end” used to introduce the last of a series of points or actions
“lastly, I would like to thank my parents”
Following words can be used instead lastly
1. Conclusively
2. In a Nutshell
3. To Summarize
4. Wrapping Up
5. Summing Up
6. Finally
7. Ultimately
8. Eventually
9. Last But Not The Least
10. At the end