The guys covered a lot of good stuff that I use. I would add that a wider stance, since you're using low bar, helps as you add on weight. Women tend to have wider hips and longer femurs than men and can get away with a more sumo like stance. This helps you have more stability and also helps you out of the hole.
Sometimes it really is mental - I load the bar and walk out with the weight I'm trying to move up to, usually 5 lbs over what im stuck at. I get a feel for it. I rerack...then I walk out again. I attempt the squat, and often on the first try I don't get down very far. I rerack...think about how it felt on my back, about where my weakpoint was (often it's my core and lower back or tightness in the hips). Then I try again. Often I get a bit lower. Then I get back to my working weight and do more sets.
Next session I can usually get to almost parallel. I just practice. Half the battle of squats is practicing the form, getting used to the feel of the weight on my back, assessing my weak points.
When I get to a single, good form rep finally, I have a dumbell handy and get right to some goblet squats. It helps even out the load on your back because in the early days of moving up, especially as you get to 1.5x bodyweight and above, you're probably engaging quads and using a lot of lower back until the weight becomes more familiar.
Squats are a total exercise for me and being mindful of my hips, core, glutes and hammies means a lot of different exercises to get them firing in unison. It takes practice and patience, especially for women as we aren't used to pure strength movements.