Stress for contrast:
“I prefer tea; HOWEVER, she prefers coffee.”
“UNLIKE my sister, I love travelling.”

Connected speech:
“in contrast…” → “in-KON-trast”
“on the other hand…” → “on-the-UTH-er-hand”

Speaking practice:
“What I expected was different; in contrast, the result was surprising.”
“She is confident, whereas he is hesitant.”