Being more aggressive usually comes down to sereve and return as well as mindset. If you can keep your serves and returns short and difficult yo attack you will get more chances to kae the first attack yourself. Then you need to always be looking and ready for your chance to attack with a topspin or a flick.
Also if you can learn to play with a good amount of spin this will helo you be more aggressive as you can go for power but still maintain good safety in your shots. So practice going for more spin by really closing the bat angle and focusing on hitting the top of tbe ball with a high acceleration!