For level 30 go with 18/18 balanced build, if you like to hit hard with a bit slower speed
Level 30 (4 420 577 xp)
* Strength: 18
* Agility: 18
* Hit points: 63
* Converted: 2
* Ironflesh: 5
* Power Strike: 6
* Shield: 6
* Athletics: 6
* Riding: 0
* Horse Archery: 0
* Power Draw: 0
* Power Throw: 0
* Weapon Master: 6
* One Handed: 156
Or 15/21 build if you will rather do less damage, but at higher speed.
Level 30 (4 420 577 xp)
* Strength: 15
* Agility: 21
* Hit points: 58
* Converted: 2
* Ironflesh: 4
* Power Strike: 5
* Shield: 6
* Athletics: 7
* Riding: 0
* Horse Archery: 0
* Power Draw: 0
* Power Throw: 0
* Weapon Master: 7
* One Handed: 165
It's a matter of personal preferance really, both builds are good and used by most pure shielders. It would be very easy to go hybrid as well, just put the points from IF to throwing.