Patch 7.20 shook up DOTA in a huge way with many hero and ability reworks, several new items, a rework to the map's layout, and plenty of balance tweaks. One of the changes that caught my eye was Tidehunter's Anchor Smash now being an instant attack rather than a simple physical damage nuke. Though this wasn't even considered to be an ability rework, I believe this to be one of the most significant hero changes in terms of altering playstyle in all of 7.20, up there with the likes of Dazzle, KotL, Rubick, and Naga. Previously Tide's playstyle was rather simple, get as tanky as possible to be able to stand in the frontline and stack auras to make your team tankier as well with items like Pipe and Greaves. With the change to Anchor Smash, I believe that Tide's role has shifted a bit more towards being a semi-carry rather than a tanky, walking ult. This playstyle turns Tide into a threat outside of teamfights, being able to dish out great physical burst damage while also reducing enemy damage output with Anchor Smash's debuff and Kraken Shell, making him a rather strong anti-carry.
For the first few levels Tide's skill build is rather flexible, but by level 3 I would always recommend being 1-1-1. Gush can be skilled level 1 if you need the slow, armor reduction, and damage for first blood, level 2 if you intend to get aggressive early on, or level 3 if you took a more passive approach for the first two levels. Kraken Shell can be skilled level 1 or 2 if you anticipate taking a fair amount of harass without being able to punish it. Anchor Smash can be skilled level 1 for a low mana cost nuke that helps you trade more favorably or secure a last hit. I could see going 1-0-1 or 0-1-1 at level 2, but i don't think that 1-1-0 could work too well.
Anchor smash will be maxed first as it is your main tool for farming and fighting. The cooldown and damage scaling combined with the items that we will purchase allow for you to one-shot the ranged creep at level 7 and two-shot the rest of the melee creeps with your anchor smash which will enable some rather efficient creep cutting. A second point in Kraken Shell is taken before maxing gush as this doubles the damage block, making you take 0 damage from creeps without having to use Anchor Smash. Gush is maxed second for even more damage and armor reduction to increase your kill potential. Maxing Kraken Shell second is definitely a viable option if you're dying a lot.
Level 10: Movement speed it nice and all, but getting essentially two extra levels of Gush is quite significant early on.
Level 15: Anchor Smash already reduces damage significantly, unless the game is quite clearly ending very soon, I would recommend taking the additional XP gain to get your level 20 and 25 talents more quickly.
Level 20: Damage block falls off extremely hard as the game goes on, if this talent was at an earlier level then it might be considered, but this talent is quite useless, especially when compared to an additional -5 armor to Gush when armor is more impactful in 7.20.
Level 25: Unless you happen to have the sole teamfight ability on your team and you truly cannot fight without Ravage, you'll want to take 250 damage every time, it's the main reason you're taking +40% XP gain after all.
I skip Stout Shield on Tide because Kraken Shell works better than it with just one level. Some people still get stout shield because they don't intend to skill Kraken Shell for a bit, but missing out on the damage block isn't much of a big deal, I much prefer having three extra mangoes. Getting lots of regen is essential for applying pressure properly in lane and making sure you don't fall behind.
Quelling Blade is obviously essential for melee heroes that intend to hit creeps, both to make sure you don't get denied and to jungle faster. Treads are my boots of choice for Tide because he utilizes the whopping 30 damage and 315 health very well while not caring much about the benefits of other boots. Movespeed and armor from phase is nice, but the attack speed is kind of bad and they're more expensive than treads. Arcanes alone can solve your mana issues but we're buying soul ring for that. On top of this, to sustain the health lost from soul ring as well as harass from enemies I buy morbid mask to upgrade to Vlad's shortly after. Since Anchor Smash is now an instant attack, you lifesteal off of every unit you hit with it. Using Anchor Smash in a creep wave heals you rather significantly.
Vlad's gives Tide many desirable stats for tide, mainly the lifesteal, armor, mana regen, and damage. All this and more is shared to your nearby allies as Vlad's is almost entirely just the aura it provides. In the build order section I have only Vlad's and Blink in the Core Items section, but I would not recommend purchasing them in this exact order. More often than not I will get an item from Situational Items before I end up getting Blink, most often Pipe. Blink is used to get into a better position when using your ult so that the you both hit more enemies with it and give key targets less time to react with a BKB or something similar.
Halberd: Need to disarm a specific hero and/or need to tank up.
Lotus: Need a dispel or against TB or Venge.
Pipe: Enemy has heavy magic damage.
Shiva's/AC: Need armor. Depends whether you need the additional pushing power of AC or more durability from Shiva's attack slow aura.
Solar: Relatively cheap way to buff up your carry or increase the enemy's armor by even more.
BKB: For when you just want to be able to stand in a fight and hit people.
Magic Stick: I feel like Tide can skip Stick most of the time, though it's still quite good against heroes like Bat, PA, Bristle.
Echo Sabre: Basically just an item you can get if you feel like you don't need any of the other items previously mentioned.
Daedalus: Huge damage buff. Much like Sleight of Fist, the crit damage also adds the bonus damage from Anchor Smash.
Skadi: Tanks you up quite significantly and allows you to kite enemies through spell immunity.
Satanic: Basically an upgrade to the main draw of Vlad's while also giving more damage and sustain.
Nullifier: Even better than kiting an enemy through BKB, you could prevent it altogether. Gives a good amount of damage and armor as well.
BoTs/Refresher/Moon Shard: Ultra late game items for all heroes, though Tide is one of the rare heroes that can utilize Refresher quite well, just make sure you have at least 1025 mana before buying it though (that is, if you intend to use your second ult in quick succession).
As Tide, your goal in lane is to make effective trades and make the enemy carry too scared to walk up to the creep wave and build up an advantage from there. With some additional disable, Tide and an ally can very easily get kills with Gush's armor reduction and slow. Treads are a huge powerspike for you, giving you 30 extra damage and 315 health, so once you get them you should aim to get more aggressive.
Once the laning stage is over normally you should have Treads, Soul Ring, and Vlad's and be on your way to completing your next item whatever that may be try to group with your team and make your goal to destroy the enemy's outer towers and establish map control. Most enemy supports should be food for you as well as some of the squishier mids without escapes, such as Zeus. You're tanky enough to sit in the front and smack towers, especially once you get more levels into Kraken Shell. If you do happen to get low, try to heal up by Anchor Smashing some creeps and continue pressuring the enemy to turtle as much as possible. Try to encourage your team to kill Roshan once you feel like you're hitting a strong powerspike such as you getting your Blink and your cores getting BKB or something similar.
As the game goes later, you should be using your ult as close to key targets as possible to make sure that they are unable to react and build items that aim to make you last longer in fights rather than damage as your +250 damage talent should be mostly enough. Items like Skadi and Satanic will give you a lot of health and Satanic enables you to keep your health up in the middle of a fight.
Tidehunter has had a reasonable shakeup to his role in the game as of 7.20, and I have found this build and style to be much more fun and successful than how he was previously. I hope that readers of this guide may also find the same results.