Not sure if this strat is used in NA but right around the time I got into D2 on EUW, I started focusing on sabotaging the enemy jg constantly. Everytime he was on the map, I'd push in my lane, make it seem like I was headed to mid or top and just head right into his jg. Most of the time they stay close to the area I seemed to be going in order to counter gank, in truth I was setting up wards, stealing monsters, and making sure they were behind enough to where they'd be more of a liability than an asset if they came to gank.
Another thing I did around diamond was trying to spoon feed the teammate that I had the most synergy with. Didn't matter if they were the support, jungler, mid, if I saw an opportunity that only we could pull off, I explained it to them and most often than not, they'd know what I was expecting when I triple pinged as a warning.
On a side note: Not every strategy is limited to a certain elo. Even the simplest ones can prove most effective when climbing.