So dredgeline is always the first skill you get but the last one to max out. The use of the skill is not the damage it does but the pull and suppressing effect it has on enemies. It has secured many a pre-creep first blood for me and my carry. Unlock riptide next as this is your main damage dealig ability and it also slows enemies. It can also be used in the middle of a creep wave to allow your carry to one shot all the creeps for a easy farm. Next get titans wrath for your shied plus additional damage over time effect when the shield is active. Unlock your ult as you can. Max out riptide first, followed by titans wrath and dredge line last since like earlier stated you just want the pull. A good combo is a dredge line suppresing the enemy titans wrath so your attacks do bonus damage hit with a basic to root them and put in some damage and riptide so they take damage and are slowed as they try t escape hitting all rings of the explosion also allowing you and the carry to pump damage into them a exhaust will slow them further if they somehow survived that and the popup from your ult will undoubdtly ensure the kill.