Yup, I'll reiterate the above. Don't answer everything and sundry. Control what you need to control and leave the rest of the table to figure it out. Don't overextend, and in terms of a win it's important to just pick your window and make sure all of your eggs aren't in one basket.
I run
Dralnu, Lich Lord as my control, and with his first ability being somewhat suicidal I need to fly under the radar somewhat. That works fine for me as I run a reanimator shell and don't often have an expansive boardstate. The deck took a bit of a punch in the guts with
Paradox Engine being banned, but I've got a pretty good list running at the moment, and I've kind of made it a pseudo-storm/copy spell shell that's capable of putting together a fairly tidy amount of resource and making some explosive plays, holding the table at bay and winning in a way that's enjoyable.
The key for me has been making sure what you're playing is excellent at what it does or gives you something for free/value for little. Pieces that I run like
Primal Amulet // Primal Wellspring and
Twinning Staff help me spread further when I'm ready to turn the thumbscrews, but otherwise things like
Mystic Confluence,
Toxic Deluge,
Cyclonic Rift and
Black Sun's Zenith make sure you're keeping everyone in check rather than just one person, or in the case on Confluence, you're dealing with something you need gone, but you can cantrip with it too.
A lot of successfully running control comes down to having the right elements at the right time, in my experience, which potentially means tutors, but not necessarily so either. If you're drawing enough over and above one per turn you will obviously find yourself with many more options.
Consecrated Sphinx,
Vilis, Broker of Blood and
Notion Thief do well for me, as well as wheel variants, and the classic
Fact or Fiction. And you needn't worry about holding on to all of them either, a 7 card hand is sufficient for everything you'd need, especially with a commander like yours or mine - we can even turn those extra cards into value in many ways. Aside from card draw, synergy is pretty important too - drawing cards that'll ampify the others you're playing makes most of your draws optimal rather than having to dig desperately for what you need.
The essence of successfully piloting control is knowing when to play reactive and when to play proactive; the tendency with control is to counter or remove as much as you can, and this is wrong. Remove only what needs to be answered - that way you're allowing your opponents to commit to their win conditions and stumble when you pull the plug on them, overcommit to the board so that you can be extra efficient with your answers, and of course you look a lot less threatening if you don't answer everything the board casts. There's even times it makes you look like an ally, which only helps. And of course, it allows you to stockpile for your moment of opportunity, at which point switching into proactive mode has maximum efficiency.
In terms of specific win conditions, I'm not sure about Grixis, but there's a couple of nice ones I use:
- Psychosis Crawler is oft overlooked, but does great work. My current favourite pairing is with Peer into the Abyss.
- Exsanguinate and Torment of Hailfire obviously are excellent, and it doesn't take a ton for either one to be quite backbreaking.
- Wheels and Bone Miser (or the crawler) makes for a pretty one-sided board state.
- Massacre Wurm just got a reprint and ends games nicely.
- Mizzix's Mastery seems like a one-card win in a Kess deck, but obviously that's pretty untested advice.
- Bolas's Citadel - it's an absolutely obscene value engine. You can combo with it, but you really, really do not need to, it's just bonkers on its own.
There's a couple of other easy win cons that I personally dislike but know are pretty effective in
Laboratory Maniac and
Thassa's Oracle. To me these are kind of antithetical to control, because why bother with the intrigue if you're just going to flip the 'win' switch? But that's just how I roll.
Hope this helps. Control is a fun shell to run because it's not just about running the best, most expensive cards, it takes the right pilot to make the right choices at the right times, and that's where this game is at its most fun, in my opinion.