pohvaliti

1. (+ acc.) to praise; to commend
   Profesorka ga je pohvalila za odličan rad. — The teacher praised him for his excellent work.
   Moram da pohvalim kuvara, ručak je bio sjajan. — I have to compliment the chef, lunch was great.
2. (pohvaliti se + instr.) to boast; to brag; to show off
   Pohvalila se novim telefonom čim je ušla. — She showed off her new phone as soon as she came in.
   Ne mogu da se pohvalim nekim uspehom ove godine. — I can't boast of much success this year.

One praises someone for something (pohvaliti koga za šta) and boasts of something with the instrumental (pohvaliti se čim).