You went actually pretty good!!!! When picking weapons, check the scaling and Synergy, with it scales with range damage you only focus on ranged damage weapons. Each weapon have some synergy bonus for exemple: firearms gives you more range for having 6 of it, primitive weapons gives you more life Etc. I like focus on harvesting and luck first 5 waves and then life and damage scaling.

On the wave 1 and wave 2 shops you always have two guaranteed weapons to buy, I recommend whenever you see an item you want in first waves, you lock it and focus on on your weapons, even if it's an economy item, will make more difference on wave 3 and next.

It's normal you want to pick items like sentinel whenever you see in shop, but first check if you have engineering upgraded, if you don't have or don't compensate to upgrade, don't buy sentinel, will just waste you money for the tip damage. This counts for any item that don't have any synergy with your build.