At the moment of the screenshot we are leading by 7.
We have 25+(7+7)+(2+7+7)-4 = 51 points. Our opponent has 32+5+7 = 44 points.
Since we have no scoring opportunities (except 5 black in row 5 for 1 point) and our bottom row is already partially filled (i.e. discarding the next tiles are -2 each while being only -1 for our opponent), it looks grim.
Taking 1 black (for discard, i.e. -2 points) will lose since our opponent will take the other black for row 2 and 7 points. There are 2 white, 2 yellow and 6 blue in the middle and it is our turn -> we are losing big.
Taking 2 white (for dicard, i.e. -4 points) will also lose since our opponent will take the one black (7 points) that brings all tiles together in the middle. There are 1 black, 2 yellow, 6 blue in the middle and again it is our turn -> we are losing big again.
The best (and only?) plan is certainly to force to opponent to take many blues in the end, optimally all 6, for -11 points. For the moment I am too tired/lazy to calculate that through. Taking 1 yellow from the middle, or 1 blue from the 4th plate seem promising starting points for analysis...