If you don't have something that threatens your opponent, then you can't threaten the opponent. So, how do you develop something that threatens an opponent?
You can't do it by just training everything equally each session. You need to spend a huge amount of time developing the things you can do that can threaten opponents. If you train everything equally, you'll tend to do everything at about the same level, and so will have nothing that threatens opponents unless they are weaker players.
The first step is identifying what it is you might be able to do that will threaten an opponent. To use a common example, suppose you believe you can develop a very strong forehand. Then you need to spend a lot of time developing 1) your forehand; 2) the footwork to get into position to play the forehand; 3) serves that set up your forehand; 4) receive that sets up your forehand; and 5) rally shots that set up your forehand.
Once you've identified the aspects of your game that you need to develop in order to develop something that threatens your opponents, the next step is to practice those aspects. And here you may face a problem. If you have limited practice time, you may not be able to get enough time to really develop those aspects. So what do you do? You make time - but perhaps only temporarily. (If you can't find the time to practice, then you simply won't improve.) Perhaps make a deal with yourself that you will put in extra practice time for a set period of time - perhaps six months to a year. Once you've developed those techniques, you have them for a lifetime! (Assuming you keep them tuned up.)
Here's a tip on practice I've always advised to players: "Practice everything you do in a match, but focus on fixing the weaknesses and developing the overpowering strengths." A sequel to this might be that, if you can turn a weakness into a strength, your game will go up a lot.