Warder and Spells Strategy (level 30)
At level 24, Endure Disease became scribeable, and at 29 Enduring Breath. I haven't mentioned them earlier because I haven't seen much use for them at these levels. Essential spells at 30 are: Spirit of Herikol (new warder), Herikol's Soothing (pet heal), Sprit of Inferno (pet proc), Spirit of Wolf, Spirit Strike (nuke), Spirit Strength and Turtle Skin. I'd also buy Summon Food for more practising, and Shrink, if you plan on fighting in dungeons. That covers almost all of them!
The next spell level is 39, and that's a long time to wait using the old, 33 hit point heal from level 22. You get another good nuke at 34, so keep practising evocation. You'll also notice that your warder isn't quite the killing machine that he was at earlier spell levels; a big improvement, but will need help to kill the mobs that you are hunting even at 30. Soloing becomes a little harder now, and groups are worth seeking out. When soloing, you'll want to pull back to cast and move forward to melee and take damage away from your pet; sometimes you'll just sit down and play 'pet cleric', with your new heal that will take care of around 35% of your warder's hit points.
Through out the spell level, you will want to stay hunting mostly the same level mobs, because your warder stays the same level. You will be able to tank better towards the end of this level, but the relative level of your warder will be getting much worse. At 36, your warder will turn light blue. To kill mobs that are dark blue to him, he will need a lot of help from you; Ice Spear, the nuke you get at 34 will help with this. You should drop Spirit Strike at this point: it does less damage for more mana, and its only advantage is the faster recast time.
The best strategy is to move in and out of combat to balance your hit points and the warders; as you start to get low, move back and let your pet tank. Whatever you do, don't get below 40%, as you may find it impossible to shake off the mob due to low hit point aggro. Keep casting Fleeting Fury on your warder, as the dexterity boost will help it to proc more often.
In a smart group, you are there for DPS (damage per second), which means always meleeing alongside the main tank and your warder, and using your pet heal between pulls. If there isn't a shaman or enchanter in your group, always cast Drowsy on every mob. You may need to ask the groups cleric/druid/shaman to specifically buff and heal your pet, as only an experienced one will be paying much attention to it. The warder will benefit from haste, dexterity, HP, AC buffs, and possibly from strength buffs, in roughly that order.