Never miss is hard to come by, but you can get quite a good attack at your level.
For an Archer Ranger there is no reason not to put 18 before racial modifiers on Dex. If you are sure you never reach level 14, 17 is sufficient. Increase it every chance you get.
Attack: 6(half level) + 5(attributes) = 11
Take any race that gives a Dex bonus. If you want to make sure you hit, Elven Accuracy and Heroic Effort (human) is great.
Attack: 11 + 1(racial Dex bonus) = 12
Superior Crossbow has good damage and range, and great accuracy. It is a bit feat intensive, as you need Speed Loader, but at your level you can afford it.
Attack: 12 + 3(proficiency) = 15
At your level having a +3 Frost weapon is quite reasonable.
Attack: 15+3(enhancement) = 18
Crossbow Expertise is a must, depending on your DM and your minor actions, you might also need Speed Loader.
Another feat is needed to get Combat Advantage as often as possible. If you can not convince your melee Leader or Defender to take Vexing Flanker, but they are good at tactical positioning, take Distant Advantage. Otherwise take Wintertouched for accuraty, as you have Lasting Frost for damage.
Attack: 18 + 2(expertise) + 2(CA) = 22.
At level 12, an average Standard monster has an AC of 26, a Soldier 28. You can hit it with a roll of 4 and 6, respectively, 85% and 75%. It is quite good, especially combined with Elven Accuracy or Heroic Effort.
I assumed in all steps that you exclusively use Twin Strike, since that is the only viable choice if you really want to optimize your damage. As a Striker you should.