What's the best way to maximize the damage from Ziggs' abilities? I understanding positioning is key but sometimes I misplace my bombs and they don't hit their mark.
Manage your mana. A lot of people will tell you to harass with Q, and usually, that's the right thing to do. Keep in mind though that...
1. Unless you're actually successfully harassing with Q, you're just throwing away your mana and weakening your own lane phase.
2. If you're not combo'ing a landed Q with a passive empowered auto attack when they're in range, you're losing a tremendous amount of lane pressure.
3. Just because you can land a Q, doesn't mean you should in lane. You never want to be in the position to where you have enough mana for a Q or a W but not both, because that can absolutely mean your death.
Tips for W:
1. Start up a custom game and just practice your W jumps. You can jump over the standard jumpable walls with it so learn how to do it. Very important.
2. Trying to catch up to an enemy that has some distance on you but is almost dead? W the ground, propel yourself forward with said W, and Q in midair at them. Yes, you can use your abilities while in mid leap.
3. Use it to zone. Is the enemy team chasing you? Your W is great disengage, toss it in front of them and 99% of the time they'll stop immediately. If not, reactivate it as soon as they get into it as your goal is to blast them away. If you wait too long, you'll blast them towards you.
4. ... following up on that last point, blasting them TO you on a disengage isn't always a bad thing if your team is ready to turn and take advantage of the short stun and get a pick.
5. Speaking of picks, your W is an amazing tool for it. Someone on the enemy team out of position during a rotation or a siege? W behind them and activate it instantly so that they're propelled forward. Your team (if smart) will take advantage of this and murder them.
Tips for E:
1. Getting chased? Your E is also great for disengage as it applies a slow. Don't throw it -at- your enemy in most cases, throw it on top of yourself while running away. This ensures that you're not wasting it because it has an arm time (albeit a short one). If you throw it at your enemy they may pass through it entirely without hitting any of the mines due to the arm time.
2. The money maker. Need to push a lane and roam fast? E, Q, bye minion wave.
3. Your E is what stalls games. Is your team behind? Awesome, Ziggs excels at stalling the game with the waveclear from his Q and E. If you have an ADC that is also capable of decent waveclear, you can beat back any siege with proper positioning.
Tips for R (I don't always suggest these as your ult is crucial to teamfights):
1. There are highly situational uses for it outside of the "press R to nuke and win". Did your enemy midlaner disappear around the time of the 2nd bluebuff? If you're feeling super ballsy, toss your ult at their blue buff. It doesn't work often, but sometimes you'll get the steal.
2. It gives you vision. It's not always optimal, but if you absolutely -need- to check baron without face checking it, toss your ult at the pit and it will reveal what's going on.
3. Is a side lane pushing against you at a really bad time? Throw your ult at it to clear it without requiring anyone from your team to split to take care of it.
There's more, but I'm at work and this is just what I thought of off the top of my head.
Also, most of the time I find it more valuable to go Athenes->Sorc Boots->Void Staff->Deathcap. The voidstaff gives you a better punch midgame and is a cheaper pickup.
Full build would be Athenes/Sorc Boots/Void Staff/Deathcap/Zhonyas (if they are bursty)/Lich Bane for fast tower pushing.