It's hard to say what your doing wrong in a bunker without seeing you,
but I used to and a lot of people I play with struggle with the same thing and when I see them hit their shots they are just not giving themselves a chance with just the set up.
Now I don't know if this is standard way to do this but it works for me. I have a wider stance and more open and needs bent a little more so I'm lower. I open the face (Not by a lot mind) and have the club a little lower than usual. My weight is probably 65-70% on my left side (Right handed golfer) and it stays there all through the shot. I "think" I have a bit of a steeper swing I don't know for sure though.
Mostly always use your highest lofted club well at least to begin with.
Here are some things I see from my playing partners.
1. They don't stay in posture and when coming into the ball they try and help it up, Lean back ending up in a big chunk or a blade, Why I try and feel the weight stays on my lead side throughout the shot.
2. They get to timid with the shot, They'll come into the ball and not hit it hard enough. If you're doing a bunker shot correctly you should be taking some sand just before the ball so you need to stay committed and hit it hard. Just think the harder you hit it the higher it will go and a lot of bunkers you'll need to have this because you need to get over the lip.
If you get time to practice just dedicate a slot of time to practice these bunkers shots. It's mostly always confidence why they above 2 points happen. They just don't trust the loft of the club to get them out,
For shorter shorts and this is a bit ironic because my short game is a shambles at the moment
but I play by feel, I'll do practice swings until I feel I know it's right then just step in and try and repeat the action. You can try the wedge matrix though this is basically 1/2 swing, 3/4 swing and a full swing, With all your wedges. So if you have 3 wedges you have 9 different shots you can play.
For general advice I'd say get the ball on the deck as quick as possible and take the relevant club. Today I had about a 70 yard shot to a back pin, With about 40 feet of green and 30 feet of it being uphill. I took out my 48 degree wedge and normally I'd be pretty confident with this shot, but I didn't catch it right not bad just not perfect and checked up into the up slope and left me with a putt of about 25 feet. I then played 3 balls with a 9 iron and played the same kind of shot, being a 9 iron I had a shorter swing meaning better control and could just run it up the green. All 3 balls were inside like 12 feet.