Enjoy playing wisp? Here is a tiny guide on some tips and tricks you perhaps dont know about.

I have nothing better to do right now, so why not? I will go through each skill and talk about things that you may not have thought about. I assume you already know what each skill does.

Tether

1. You can use tether on something relatively far away to quickly travel there, abuse it! It is perhaps one of the more obvious tricks, but it is probably the one with the most depth too. It is a premium escape mechanism and one of the best skills in the game to initiate with.
2. When someone disables help, you can't tether that person. Keep that in mind when playing in pubs! You don't want to quickly tether with someone and ultimate somewhere only to realize that the guy you tried to tether has help disabled, and you are now alone vs the people you planned to gank...
3. When you ultimate with tether on someone, the tether duration is refreshed back to 12 seconds, the exact same amount of time that your ultimate lasts for. However, the cooldown of the skill is not affected.
4. the unit you are tethered with only gain health/mana when you gain hp/mana. The point here is that your friend will get zero regen if you have full health/mana.

Spirits

1. Have as habit to always toggle your spirits in, in combination of your ultimate as close as possible on someone, you will VERY quickly explode all of your spirits, giving you some formidable burst damage. the same applies when entering a battle with tether. You generally want to find someone that stands behind an enemy, the tether will stun your enemy for a long enough time for you to fly "through" and explode all 5 spirits on the same person.
2. You can make your spirits "stop" at more places than max and min. Simply pressing out/in twice makes the spirits stop where they are.
3. The spirits explode in an aoe, so you can actually farm creeps simply by hitting an enemy that stands close to creeps. Useful for turtling!
4. Jungling with wisp later on in the game is the way to go! You are the support and should try to avoid stealing farm from others who needs it more. Activate your spirits and go kill a camp with the help of the aoe damage. then quickly head over to the nearest camp before you spirits explode. The damage from the exploding spirits is pretty close to a oneshot against most camps.
5. From level 2 and onwards the spirits have longer duration than cooldown. if you activate spirits again when already having them out, the ones that are out will explode. This is very useful since if you have them at close to melee range you can get all 5 spirits to instantly pop dealing insane burst to one or more targets.

Overcharge

1. This is related to the previously mentioned (4.) in tether. One level in overcharge at lvl 4 is sometimes necessary to be able to help regen the health and mana of the guy you are laning with. Wisp's itembuild is all about abusing the regen with tether. And overcharge is what makes it possible for you to abuse it to the max. in 6.75, overcharge was changed to drain more health/mana. I would like to note here that it was not a complete nerf. While generally bad in lategame, this was a buff to wisp's supporting potential in the early game, giving you a higher potential to quickly lower your hp and mana to help regen your friend who is in trouble.
2. There is no penalty for activating and deactivating Overcharge, Treat it like phase shift! when you know there is incoming damage, activate, when you know there isn't - deactivate. Overcharge may seem like a simple skill, but it gets far more complex the more you play around with it.
3. Overcharge drains a % of your CURRENT hp/mana, making regeneration far more important as opposed to straight up HP. When building items for wisp, keep this in mind. Heart is still a great luxury item because of its regeneration, but simply stacking HP is a very bad idea considering you want to have overcharge active most of the time in the lategame to help your carry out.

Relocate

1. If you are in a hurry, consider using your ultimate before tethering your friend. After having used it, you have 2+(depending on ulti lvl) seconds to tether your friend. It gives your opponents less time to react to what is happening if you are trying to flee from someone, and if you have no communication with whom you are tethering, it gives that guy less time and chance to break your tether.
2. When ganking someone that is farming, use your relocate directly on top of the guy. Nobody is watching their character when farming, their eyes are always fixed on the creeps (and depending on skill, the minimap). If youre lucky, this also gives you an instant tether stun and 5 exploded spirits on arrival. Naturally, this applies more to ranged heroes than melee ones.

That's it! I don't want to go into itembuilds and playstyles since there are more than one way to play the hero, and I think people listen more to pros than some random redditor regarding such things. The only thing I want to say in the matter is that wisp is a surprisingly potent hero in the solo mid position if you ever get the chance to try it out. (spirits HURT!)