I'm right handed, but sometimes a left handed shot is needed and sometimes a mechanical bridge (rake) shot is needed. I was very bad at both of these...
Then I started practicing these shots once a week. I would shoot in a rack of balls left handed and then shoot in a rack of balls with the mechanical bridge. Shooting left handed was *very* frustrating at first. I line up shots with my right eye, so I learned that if I move my head over a bit for left handed shots and use my right eye, I make more shots.
I am now fairly good at these shots. It is still uncomfortable shooting with my left hand, but if I need to, I can.
And remember, when first practicing shots which are difficult for you, it will be frustrating. But after a few months of regular practice, you will start to notice improvement. It is good to practice the shots you are not good at, even though they are frustrating. After about 6 months of regular practice, some shots will not longer be frustrating, but fun!
For practicing with the mechanical bridge, I break the balls, then use the mechanical bridge for each and every shot. I'll stick the mechanical bridge on the rail if the cue ball is near the rail. This practice can give you an advantage since many players do not practice shots with the mechanical bridge. I hold the bridge with my left hand while shooting (then I can quickly remove the bridge from the table to keep balls from hitting it). I hold the cue in my right hand with my elbow about where my bellybutton is and my hand is under my chin. Then I take several practice strokes and may move the mechanical bridge a little this way or that way until it looks just right. Then a few more practice strokes and then I shoot....