timming leafs??

Im on my day 12 flowering and was wondering if i should trim off some leafs i heard that its good do do this ne advice please????

Once flowering you don't really want to trim much...trimming is more for the Veg duration. If you have a ton of leaves and there are a few covering good heads you want exposed to the light to make buds, you can trim that but that's where I would draw the line.

You'll notice towards the end of flowering that the plant will kill some leaves to utilize their stored energy so you really need to keep everything you can.

I take clones up to the 3rd week in flower I do this to try and keep a half ass perpetual thing going and to have the plant focus on the upper bud sites.....but for the most part I only cut fan leaves that go to the branch I remove....

IMO, you shouldn't trim anything, until you have become more confident with your growing skills. I've experimented with trimming before, and never seen any noticeable difference in yield, between a trimmed, and untrimmed plant. But, I can tell you that it's easy to hurt your plant, if you get carried away with the trimming. It'll kill your yield, if you stress it too much. Honestly, I don't think you should risk trimming, because they will be perfectly fine if you leave them alone. You'd be much better off if you looked into LST(low stress training), and used that method to get better light penetration.