I often use GoWiPe in my clan wars, and I can tell you that there are an array of things that can go wrong. Sometimes, those things are out of your control (Archer Queen bashes her head against a wall going towards a Gold Mine while the Town Hall lies undefended), but most of the time, they were either in your control from the very beginning of the attack or a better decision should have been made during the course of it. I am a non-rushed Town Hall 9, and have been using GoWiPe for awhile. Here are some tips to make you a better GoWiPe user.
1. Thoroughly study the base you are attacking.
Certain base designs are specifically designed to give opposing attackers trouble should they decide to use a GoWiPe-style attack. The most common attribute of these bases is the use of "funneling" in one form or another. If you don't know what funneling is, it's essentially the deliberate placement of walls and defenses that leads troops astray from the attacker's intended target (usually the Town Hall). Funneling can be done in many ways, but the most troublesome bases for GoWiPe users to attack often include lots of long, L-shaped corridors. What these long compartments do is lead troops that don't prioritize the buildings they attack (Pekkas, Barbarian King, Wizards, etc.) in a straight line away from the center of the base. These corridors can sometimes cause so much confusion that even if a Jump Spell is placed precisely in the direct path the troops are taking, they decide to ignore it anyways. The best way to prevent this from happening is to either not attack bases that contain many of these compartments (while trophy-pushing) or, in a Clan War scenario, determine the best starting point of an attack that will avoid the larger of the L-shaped corridors (if possible). Also, as a disclaimer, sometimes troops will recognize the Jump Spell or still go the direction you intended them to, but a lot of the time these long compartments can prove fatal to a GoWiPe-style attack.
2. Don't drop the Pekkas too early!
A VERY common mistake that I often see my fellow clan members make is they drop their Pekkas far too early, causing them to veer off to the left and right and completely ruin their attack. The Pekkas are the driving force in a GoWiPe attack and cannot be just placed wherever and whenever. Be patient! Wait for the first enclosure to be opened before and ALL surrounding buildings within the immediate area of placement to be cleared before you drop those Pekkas.
3. Don't drop all your Wall-Breakers at once!
Failure to do this will shave crucial time off the clock and potentially do enough damage to your Golems and Wizards for it to be impossible to recover. Drop them in packs of 2 or 3! There are always people who leave Giant Bombs and Spring Traps around the edges of their base, which can be devastating if you drop all of your Wall-Breakers in one place. Also, dropping them all it once makes them highly vulnerable to splash damage, so it truly is better to drop them in packs.
4. Be meticulous in spell placement.
Another common mistake that I see GoWiPe users make is dropping their spells too early, too close together, or not fast enough. When you use 2 Heal spells in your GoWiPes, the FIRST one should be dropped when the Golem(s) health reaches below half, and the SECOND should be dropped when all of your troops are in the middle (this is obviously debatable and adjustable depending on how a specific attack is playing out). When you use 2 Rage spells, the FIRST one should be dropped once the Pekkas and Heroes have been placed in order to accelerate them to the center (also adjustable depending on the attack), and the SECOND one should be dropped while they're in the center for maximum damage potential (not debatable; at least one of the two Rage spells need to be placed in the center when your troops have entered that enclosure). Jump Spells need to be placed BEFORE the units get near the walls that they will have to clear or else you run the risk of them going astray and making your attack a failure. Freeze spells I have no experience with, but I've watched enough videos, and you need PATIENCE when using them. They need to be dropped when either your Golems, Pekkas, or Wizards (depending on whether or not the Inferno Tower is set to Multi-target or Single-target) are taking a significant amount of damage in the core of the base. You also need to ensure you hit the maximum amount of structures with the Freeze spell; don't just place it wherever and hope it hits all of the defenses.
5. Follow the path that your troops are GOING to take, not the path you want them to.
Troops frequently "disobey" and do odd things that you did not want them to. This can all be because of Skeleton Traps and Clan Castle troops, as well as base designs that make use of funneling. Adjust your attack according to what direction your troops are heading in, not the direction you hope they go in. Pay close attention to their movements, and anticipate the opportunities that you'll be given to make the most out of your spell placement. As mentioned earlier when I talked about the L-shaped compartments, troops sometimes completely disregard a Jump Spell and continue onward if it was dropped too late, too early, or not in a spot where it covers a lot of walls.
Only experience and repetitive use of GoWiPe-style attacks can ensure your success, and everyone has a bad attack once in a while. I hope that these tips make you a better GoWiPe user in the future. Thanks for reading and clash on!