If you ask me about one advise about powerpoint I’ll say one word “master slide”. It will make your life easier. Basically it is like the template where any effect reflects on the rest of the presentation. you can add logo, change color, and font. You can access it from View > Slide Master.
And to exit from New tab of Slide Master > Close
An important note though, to have a consistent result use the specified boxes for text; write the titles in titles box not just in any drop text box. This way if you make any changes in master slide it’ll be reflected on the while presentation.
So, what is it you are struggling with? Let me know if I can help.
Engineer’s Brain 