Lion is a good hero for not so experienced players. Lion is a great support, spammer, ganker, and warder! Yes Lion is such a busy hero!

Level Skill
1 Impale
2 Mana Drain
3 Impale
4 Mana Drain
5 Impale
6 Finger
7 Impale
8 Mana Drain
9 Mana Drain
10 Voodoo
11 Finger
12 Voodoo
13 Voodoo
14 Voodoo
15 Atr
16 Finger
17 to 25 Atr

Items (Primary)
3 Null Talisman or Dagon
Magic Stick
Bottle
Phase Boots
Vanguard

Items (Late Game)
Aghanims Scepter
Phase Boots or Boots of Travel
Guinsoo Scythe
Bloodstone
Shiva's Guard
Dagon 5

I tell you every cooldown of your Ultimate you should gank and you should always join the clash and I assure you it is always Goooold........ Hehehehehehe