Don't trust the (formerly) accepted answer. :-)
(It depends, in part, on a mistake you've made earlier: there's a third flag next to a couple of 2s along the left side. I added a green square to mark the bogus flag in the picture below.)
Despite that, you have several break-ins left to use:
- the flag that's next to the mistaken flag has a 1 next to it.
- the 1-3-1 corner is guaranteed to have the 1s' bombs in squares next to the 3, and a bomb in the square that's only next to the 3.
- an 1-2-1 along a straight edge always has a safe square under the 2
- at the top, there's a 1-1-1 (looks like 1-1-2, but the 2 already has a bomb) neighbouring only three squares, that can only work with a single bomb in the middle.
- At the bottom right, the 2 will have both its bombs next to the 4. Combining this with the logic propagating from the other break-ins, you can mark one more bomb next to the 4.
Here's a picture of the possible deductions.