The SKS rifle platform can truly be a Riflemans Rifle. There are a number of issues endemic to this rifle that need to be addressed:
Sights.
Short sight radius, coupled with the open sights, make for a sight picture that leaves the front post fuzzy for most shooters, and incredibly difficult to tell if you've got a proper sight picture. While everyone here suggests the Tech Sight rear aperture sight for the SKS, I humbly disagree, for two reasons:
A: Field stripping the rifle now requires a tool. Yes, it is a simply flat-head screwdriver, that most people would have with them anyways, but the rifle, as designed, required nothing more than a bullet tip for full field stripping/cleaning. KISS!
B: Elevation adjustment via the rear sight, (on the ts-200 model) requires the use of a specialized tool- without it, making adjustments are imprecise, and even with the tool, are still a PITA. If you opt to go for the windage-only rear sight, now you have to make all of your adjustments at the front sight, which really should be loc-tighted in place..
I instead prefer the mojo peep sight, which replaces the rear leaf sight on the SKS with a click-adjustable aperture. The click mechanism is stout, and you retain the ability to take down the rifle with zero tools. Additionally, you don't have to worry about fitting the tech-sight to the rifle, and subsequent take-downs screwing up your zero.
Trigger.
SKS rifles have a notoriously bad trigger, right from the factory (Russian-made SKS rifles being the only notable exception)
The problem is that none of the trigger parts were hand-fitted, and because of the machinery they were made on, all had machining burrs, and improper mating of surfaces. I *HIGHLY* recommend sending your trigger to Tom Prince AKA "Kivarri" from SKSBoards.com Mr. Prince has worked on a few of my SKS trigger groups, and I have been nothing but pleased with his work. An inexperienced gunsmith can make an SKS trigger worse, or worse yet, make the trigger dangerous, so do not attempt to work on your own SKS trigger unless you are qualified to do so.
Ammo.
For far too long, the SKS/AK rifle platforms have suffered a stigma- they've been labeled as inaccurate P.O.S rifles, hardly suited to minute-of-garbage can lid at 100yds. For some, this may be true. For the most part, though, I believe that this is ammunition-related, and I've done quite a bit of research to back this up. Long and short of it is this:
Most commercial ammunition (including USA manufactured 7.62x39) is either so inconsistent (WOLF) or uses the wrong bullet (most USA) so as to invariably give horrible groups, even from an otherwise excellent rifle and shooter. Wolf Ammo varies not only in powder charge, bullet weight, but even bullet diameter- truly the worst ammunition for shooting groups. USA made ammo uses a .308" diameter bullet, when the bore of an SKS is .310" nominally. Not a recipe for accurate shooting, even if the ammunition is match-grade consistent (which it isn't). I have only found two brands of ammunition available that shoot well: Golden Tiger, and Silver Bear. Further testing shows that both brands exhibit high round-to-round consistency, and both use a .3095" diameter bullet, which more closely matches the bore diameter...
If you really want to stretch that SKS out there beyond 3-400 yds, reloading is the answer. For details on this aspect, PM me and I'll share what I know.
Sling.
Standard SKS sling mounting hardware makes it very difficult for a shooter to adapt a USGI web sling to the rifle. With a little bit of ingenuity, it IS possible. Take a look at that brand new MidwayUSA shooting mat you just got for Christmas- notice the shoulder strap? Those quick-detach swivels are 1-1/4" and fit the sling mount on the SKS perfectly.... While it may not be as good as having the sling directly under the rifle, its a darn sight better than the standard SKS sling, which is barely useful in a hasty configuration.