Starting off with armor and pots and eventually building into a wriggles. After that you want boots, either with swiftness or if they have quite a bit of CC go merc treads. After your boots you want to start your trinity force and sheen is a great item to get first. Alternatively you could pick up phage if you are getting targeted in fights and want the durability. After you finish your trinity force, you're going to start getting tanky. Start with Force of nature or Sunfire cape depending on their team composition and whats beating you up the most. And eventually going into Guardian Angel. With this build in bear form you will hit around 550 move speed when bear is activated and you'll still do quite a bit of damage to squishies. If the game goes on for a long time, you can sell your wriggle's lantern for a bloodthirster or a black cleaver both will increase your damage a lot.