When you write a block of text, the editor will insert line breaks without you noticing. Fonts are relatively small and the resulting text blocks look always good.
Designing presentation slides is different though. The position of every word and every line break counts. You face similar problems as the headline writer of a newspaper, or the designer of a poster.
- Make sure important words that need to be seen together, stay together: "blue [break] ocean strategy" breaks the connection between critical words
- Make sure the text is balanced across the page, without weird right paragraph endings. If required, change the font size to make words just fit, or drop to the next line. Add line breaks manually if you have to
- And if it still does look weird, rewrite that headline into one that does look good
Yes, contradicting myself: my blog engine sometimes makes a mess of blog titles on certain screen sizes. I cannot control line breaks here...