Find something that annoys you while riding and then work to resolve it, avoid it, or replace it.
Example - There's a stretch of road that you don't enjoy. Perhaps its potholed, poor quality, narrow, filled with cars, or something. Find an alternative route that avoids it.
For me - traffic lights are irritating because the effort to get moving again is so much greater than speed maintenance. So I have a route that goes down a one-way street with a 30 km/h speed limit. If I enter the street right I can travel ~5 km through the CBD non-stop. Adjacent roads will have 14 sets of lights and I would generally stop at 4.
Traffic light anticipation - Instead of riding up to a red and stopping, try and predict the upcoming red lights sequence and slow down early so you're not having to stop/start.
Or simply take the long way home on some pleasant evening after work. No stress to get there, just enjoy the trip. You're able to ride for 30 minutes twice every day - so on Friday night try a 60 minute ride home. Pushing your upper bound of endurance helps the average endurance to rise.
Is there anyone living near you who would group-ride to work with you? Talk tends to make the time go faster even if you're travelling a bit slower.
Are you the personality that is motivated by progress? Consider logging your ride distances and go for a monthly total. 30 minutes each way is probably 5-8 miles each way, (or 10-16 a day) which is quite a respectable distance! 20 working days a month is 200 miles a month and that is a lot of travel - I started with 100km/month when I lived 1km from work.
Do you have bike transport on local buses, like this? You may feel more comfortable if there's an out for getting home in the evening without riding, as a fallback plan.
Final serious answer - have you considered an electric assist? This isn't intended to go faster, its to help you by taking some of the load off your legs. Its more similar to the feeling of a good tailwind, not a motorbike-feeling.
BTW - you ride a bike, and you're asking about improvements for something related to riding....