Is it actually possible to get a smooth plaster finish as a total amateur?

For those 1960s masonry walls, you're likely fighting high suction if the bare brick or block hasn't been primed. If the wall is sucking the moisture out of your plaster instantly, you’ll never get it smooth. Get a **bonding agent** or at least a PVA seal on there first. It slows down the drying time so you actualy have a window to work the material before it sets up hard. You mentioned using a hawk and trowel, but for a DIYer, a **skimming blade** or a 12-inch taping knife is usually much easier to control than a traditional steel trowel. profesional results come from two paper-thin coats rather than one thick pass. Put the first layer on just to fill the deep craters, let it get tacky, then go over it with a second "tight" coat. Don't obsess over every little ridge while it's wet—trying to over-work it usually results in more gouges.

Consistency of the mud is the biggest factor. It needs to be like thick Greek yogurt, not stiff peanut butter. If you're using a setting-type compound from a bag, mix small batches so you aren't rushing. If it's the pre-mixed bucket stuff, add a splash of water and whip it with a drill mixer untill it’s creamy and smooth. If it's too thick, you're just fighting friction the whole time. Stop trying to sand your way out of a bad application. If you have huge humps, scrape them down with a stiff putty knife while the plaster is still "green" or slightly damp. Also, get a high-lumen work light and place it parallel to the wall. This "raking light" reveals every shadow and high spot, so you can see exactly where the topographic map is happening before the mud even dries. It's much easier to fix a low spot with a dab of mud than it is to sand down a mountain later.

I’m struggling with the timing on my hallway project. That 'green' stage you mentioned—how long does that window actually last? I tried scraping a high spot about an hour after applying, and it just tore a chunk out of the finish. Is there a specific color change or feel I shold be looking for before I start scraping? Also, for a beginner, are there brands of pre-mixed mud that stay wet longer? I’ve heard some stuff sets up way too fast, and I definitely need the extra working time to avoid making a mess.

That tearing happens because it's still too wet internally. Wait til the sheen disappears and it looks matte; if you can press a finger against it and it feels like stiff modeling clay without sticking to you, that's your window. I usually use a wide joint knife to 'shave' the high spots then. For longer workability, grab a bucket of USG Plus 3 (the blue lid). It’s a lightweight compound that’s way more forgiving than the heavy all-purpose stuff. Also, keep a clean bucket of water and a sponge handy. Wiping your tools down every few minutes prevents dried crusty bits from dragging thru your fresh finish and causing those annoying streaks.