Improved Aid Another (3.5e Variant Rule)
From D&D Wiki
Improved Aid Another
In a 3.5 Game I'm part of we have a variant on the Aid another rule that improves the bonus you give based on the ranks you have in a skill. After all if you were getting survival help from Bear Grylls or Ray Mears you wouldn't get the same bonus as you would get from Myself or a random person.
The Ruling is fairly simple, as part of an aid another you will give an extra +1 bonus for every 5 ranks you have in skill or base attack bonus. Important to note that's ranks. A 5th level fighter performing an aid another in combat to boost an allies attack will provide a +3 bonus instead of a +2 with his base attack of +5. A Ranger with 10 ranks in survival will provide his ally with a +4 bonus to their check instead of +2.
The normal DC 10 still applies.