If you want something actually strong, try Bruiser Leona. Not AP bruiser, but actual bruiser.

or 
Max Q first, W second, E last. Take ghost so you're more likely to be chaining Qs off non-stop in fights.
It honestly works most reliably in the jungle, but you can take it top as well, depending on match-up. If you're in the jungle, do machete start. Your Q does over 300 damage at level one if you auto->Q->spam right click for her double auto-reset.
Her early clears can be painfully slow, but it picks up almost way too much with either sheen or cinder. Due to how much CC/engage she's loaded with, you can just grab cinder or sheen ASAP, rather than building your jungle item. Your gold income and damage in ganks ramps up a ton once you get them, rather than finishing your smite item early. You probably want to start gromp>krugs, but if your bot lane is on blue side, you can take a hard leash on Gromp. If this happens, either do a smiteless so you can smite blue, or do the fast lvl 6 clear, which is gromp, wolves, wraiths, krugs, base, gromp, blue, wolves, wraiths, red, krugs. Gank if you can, save smite for passing by red if you end up low on your first clear. You can do the same starting krugs as well, but you should be healthy enough to clear with krugs buff+Red regen to do a full clear and gank some poor unsuspecting lane. Watch out for invade junglers.
Top lane, you're literally just trying to not die until you get some CDR and cinder. Your dueling potential skyrockets once you have some ranks in Q, cinder, and sheen. Don't worry if you can farm vs your match-up because you're one of the best gank-assists in the game. Your jungler would be a fool if they didn't gank. Probably best to start corrupting potion in most circumstances. If the enemy harasses you in a good sized minion wave, there's actually a decent chance you can kill them and snowball hard because of it, due to how much minion damage you can force them to eat+the burn.
mid-late game, you're extremely tanky and end up 1-shotting carries. The reason it works so well is because you have 33% up-time on your stun, and the damage and tankiness coming with it makes you as much of a tanky damage threat as a juggernaut, almost...but without any of the kiting pitfalls.
The reason you take abyssal instead of other MR options is A), the AP brings your kit's base damage a little higher than pre-rework Leona, B) the MR reduction pushes your damage up just enough to make you a real threat to squishies and C) Its one of the highest MR options available. Due to your W, you often don't have to worry about other MR itemization.
The reason you take Warmog's is to round out that last 10% CDR, as well as provide more HP than the average item would, since you invest pretty heavily into armor/MR early via IBG (usually) and Abyssal. Again, jungle gives a much smoother defense growth because you have SotA and Cinderhulk to pad your HP early-mid before you start building significant HP.
Randuins is for crit carries/anivia/Karth/Vlad/anyone else with spell crits. Dead mans is for any other time; it makes stopping your engage near-impossible.
In fights, your main goal is to E->Q->R->Q->E->Q in order to 100-0 someone. Sometimes the enemy groups so much you HAVE to use R earlier. Use your best judgement.
To make picks, you should be able R->E->Q->W->Q->E->Q for a kill without much risk. Spam that ult if you think you can make a pick. Once you have 40% CDR, it has a 35 second CD.
If you're jungle,
is probably your best option if you want to hard carry. It lets you kill almost anyone no matter how fed. If you want to help your team out more,
or
can help as well.
Now, go on and proceed to laugh when your Q alone is chunking 1/3 of any squishy's life on a 3 second CD.