When it comes to resources, QUANTITY OVER QUALITY. Your goal is not to have an even distribution of resources but to have so many coming in (3-4 per dice roll on a decent % of possible rolls) that you can get whatever you want through trades with the bank or other players.
phase 1: Initial settlement placement
in picking your initial two settlements, attempt to satisfy the following conditions (in descending order of essentialness):
priority 1: ore and wheat on frequently rolled numbers. Try to have at least one of them, ideally both, on 6 or 8. If you can only get one on 6 or 8 go with ore. If you have a chance to really max out on ore by having it on multiple hexes go for it, as long as you can do so without neglecting wheat.
priority 2: number distribution. Get a resource on 6 and get a resource on 8. As long as priority one is met, don’t think too hard about which resources. Try as well to be on five or six distinct numbers, the ideal being 6, 8, 5, 9, 4, 10.
priority 3: sheep. You need some sheep to get dev cards to keep the robber off your ore and wheat. Doesn’t need to be a super frequently rolled number.
priority 4: brick/wood—these don’t matter as much as they seem to. Try to get at least one, especially if doing so is how you fulfill priority 2. “I’m on brick, so I should also be on wood to build some roads” is a FALLACY. Resist the temptation to build roads early!
phase 2: gameplay
step 1: Before building ANYTHING else upgrade your two initial settlements to cities. Build a road or buy a dev card only if you’re really worried about losing everything on a 7.
step 2: Build a third settlement. If you’ve done everything right up until this point, you’ll have such a good influx of resources that trough trades with players/bank this will be easy even if you’re not on any wood/brick. If possible build this third settlement on the best available port.
*the following two steps may also work in reverse order; I’m listing them in the order in which I tend to do them*
step 3: build a fourth settlement — if your third settlement wasn’t on a port this one should be.
step 4: upgrade your third and fourth settlements to cities. This puts you at 8 points
THROUGHOUT steps 3 and 4 buy dev cards like crazy to get either largest army or multiple victory points
step 5: win