Mina has a significant range advantage and it seems better lows over all. She is safer than she used to be, but most of her ranged pokes still seem to give you plenty of frames, and her options once you are in close are ok, but much more underwhelming. To advance you need to either tailor the approach based on what they are doing, or push them in some direction of decision making.
Do they poke every opportunity they get, or do they wait around looking for a whiff punish? If they are consistently doing the former, step forward in increments and guard, then use the frames you get from blocking their poke to threaten their next action. If they stand/step around and look for a whiff often, just run right at them.
If they are good at mixing up their pattern and reacting to what you are doing, then you need to interact with them more, which is the hard part. Step around some to see if you can get them to whiff 1B, 66B, or 22B and whiff punish/close the distance. See if you can catch a 6A or similar high anti step move with something that ducks. If you have them poking a lot and they don't mix in break attacks, try Reversal Edge. At some ranges you can poke as well with TAS B, sometimes with a delay before the B to get more range. When you are in Soul Charge, TAS B travels much further, is still very fast, hits much harder and is pretty safe on block. Use it's threat to get in or take the damage if they don't respect it.
Once you get close try to use moves that advance you and give reasonable frame disadvantage so you can continue to be threatening. A non exhaustive list could include 1K, 4B, WR K, throws, 66B. To be able to completely cover the opponent's options you might need to use things that only advance, or that don't advance much. Some usable but not ideal options could include 66A / TAS AA for step, 6BB / 4A+B for fast highs BB, 6K, 2A and KK as interrupts. If they just freeze on guard, put them into whatever your standard mixup is.