I've been playing League for a short while (barely lvl 13) and I've been jungling with Sejuani and I'm having a lot of fun with her (even bought her Poro Rider skin). However, I feel like I've sucking quite a bit lately. What are some good tips I should take into consideration in order to get better at jungling with her?
thats cuz ur lvl13 buddy junglings a bitch without runes and masteries you stay away from all jungling champs who are below Jarvan tier ;l
now wot you do is, ditch tank yup, tanky sejuani for scrubs gotta have the DFG, scary hat with a face and scary mask with a face
take that cinnabon waving skill and max it cuz its good in the jungle kill 3 camps and go upgrade ur smite to trailblazer.. the go-to smite for all non lee sin junglers little jungle creeps actually hurt like a bitch now and you should kill them first
throw DFGs at people and bump into em and spam all ur skills.. kill em for sure dont miss ur ult, you get reported if you do
I think I can help a little bit here. Not a Sej main by far (that's my friend's job), but I've played her enough recently to be able to give some decent insight.
Few Prior Notes
Itemization Since you don't have runes, building Trailblazer + Juggernaut is perf. Let's you stick around longer. After you get defensive runes, you can choose between this or Stalker's (for early-mid ganks) or Skirmishers (for lategame tanking). Jugg will stay the same thoughout. Your core item is Sunfire. Rush this right after your jungle item. Grab t1 boots early (after your upgraded smite) and squeeze t2 boots somewhere in between the two items where you can. Tabi against AD, Mercs against AP or heavy cc. Your choice. Frozen Heart is cool if they're atk spd heavy or the fed one is). Warmogs is cool if they don't have %hp. Banshees, Randuins, Abyssal or Liandry's for dmg. You know the works. See what the enemy has, then buy accordingly.
Jungle Routes
On Blue Side, try to get smiteless on Krugs (pop pots if you have to), smite red early to get your hp back and the cd on smite, then go to wolves (b first if you're too low), then blue. If you're level 3 and see an easy gank, go for it before blue. Purple side, pretty much the same, except you might have to be sooner since red and blue are inverted. Toad->Blue->Wolves->Red. Pretty much farm up til 6, that's when your gank potential spikes. Only gank when it's obvious kill potential. "Presence" will get you counter jungled.
Skill/Mast/Runes Start w, max w. Max e second and q last.
9-21-0 Masteries, the tanky part gets priority as you level.
Hp or Armor yellows, hp or movespeed quints, atk speed reds, mr blues
I think this is most of the basics. Let me know if there's anything else.
I wrote a guide for lvl 30 so you might wanna look it here
Since you are level 13 though i would suggest going 13 points in defensive mastery and build all tanky. It's a lot easier to learn how to play sej as a tank because it's way more forgiving. when you get better trying building ap, but you really need to land abilities to be efficient with her as ap, as with anyone else.
if you have more question feel free to add me in game i'll give you some tps
My usual core build for jungling (this is only for when your team needs you to be tanky):
As of right now, the Juggernaut enchantment does very little for Sejuani's early game and the 500 health is laughable compared to the benefits of RoA.
The 80 Ap and 20% CDR from will allow you to snowball and be more of a threat.
After that, I usually grab an early 
. No matter what build you use, this item IS AMAZING for your early-mid game.
After you are starting to snowball with and , now it is time to start building towards . The earlier you build this item, the better.
Pick up shortly after and then finish .
Your final item can be a slew of things:
Any of these items are great for finishing off your build giving you more damage, tankiness, or the ability to take advantage of certain situations.
is one of my mains. She can carry games as a tank or burst mage, this build leans more towards tank. I prefer tanky jungler and Burst lane mage (top or mid).
GLHF :]
