I don't know why someone didn't ask you this right away, but which mods are you using? Because one of them is seriously altering the way Sneak behaves.
(sounds like the Sneak one that comes with The Lighting Mod, or Enhanced Stealth)
To raise Sneak effectively you need to be within the AI Radius of the NPC/Creature. (otherwise it doesn't count)
Moving back and forth does seem to help it increase faster as well.
In the original game, just the weight of your Boots is calculated when you Sneak, but some mods check all your armor.
And make sure your Fatigue is full.
The http://www.tesnexus.com/downloads/file.php?id=19510 has the option to let you toggle Sneak. Along with many other great fixes (all optional.)
This is the
Player check for Sneaking. It runs every 5 seconds.
if sneaking: sneakTerm = fSneakSkillMult * sneak + 0.2 * agility + 0.1 * luck + bootWeight * fSneakBootMultelse: sneakTerm = 0 fatigueTerm = fFatigueBase - fFatigueMult*(1 - normalisedFatigue)where normalisedFatigue is a function of fatigue. empty fatigue bar -> 0.0, full fatigue bar -> 1.0Note fatigueTerm is normally 1.25 at full fatigue.distTerm = fSneakDistBase + fSneakDistMult*distx = sneakTerm * distTerm * fatigueTerm + chameleon (+ 100 if invisible)
There is another check on the NPC as well.
npcTerm = npcSneak + 0.2 * npcAgility + 0.1 * npcLuck - npcBlindnpcFatigueTerm = fFatigueBase - fFatigueMult*(1 - normalisedFatigue)using NPC normalisedFatigueif PC is behind NPC (180 degrees): y = npcTerm * npcFatigueTerm * fSneakNoViewMultelse: y = npcTerm * npcFatigueTerm * fSneakViewMult