Concerns of The Deep? I'm Ballin'

Buy left to right
Use Splatter (1) as often as possible! Remember to dash-jump before using Goo Ball (4) once you get Arcane Surge! Buy a Lane Extra item if you're struggling then sell it later
You can also consider Cold Front during lane.

Buy one of those items if you are struggling, or to remain in lane and not miss out on souls! Sell the item you picked later.

Buy left to right
You can grab an extra active, when Goo Ball (4) is maxed, for either more damage or utility! If you are struggling to survive, check the Survival category or get items like Diviner's Kevlar earlier.

When Goo Ball (4) is fully upgraded, you can use those to deal more damage! Recommendation: Cold Front & Arctic Blast.

You can buy left to right, or in the order you wish, depending on how your match is going! Witchmail will trigger a ton in late game, resulting in a lot of cooldown reduction.

Those actives can help you create a playstyle that suits you more
Recommendation: Return Fire.

If you realize during Late Game that the enemy is building Spirit Resistance against you, then after getting Spirit Burn, grab either Escalating Exposure or Spirit Snatch
Escalating Exposure is the easiest to trigger
Recommendation: Spirit Strike & Spirit Snatch.

If you find yourself struggling to stay alive, consider one (Or more!) of those items
They will increase your survivability a lot, all depending on how your match is going and who you are facing!

These items will help you have a better time against specific enemies or simply allow you to modify your gameplay to something that fits you more
Keep in mind that these items are NOT part of the build
Decay, Silence Wave, Knockdown and Curse are powerful actives that can be bought to counter specific heroes.