hi,this is my first guide and i am not english,but i'll do my best.
this guide is the way that i prefer to play riven solo-top. in the early game tanky,then
with also a great damage and a good attack speed. with this build you have just to pay attenction to not die in early game when you just have boots of speed,then is all easy and you will be very hard to kill.
in this guide there is a build that allows us to play very safe and easy our riven : never die
and a lot of kills.
the skill sequence is very variable,it is based on how we want to play. i never upgrade E because i prefer Q but a lot of builds suggest to upgrade E so do what you prefer.

pros :
- high mobility (hard to be ganked)
- manaless
- damaging AOE stun
- great farmer with Q at level 3 or more
- RIVEN DOESN'T DIE

cons :
- attenction early game
- need good timing with skills

my choice :
a riven with flash combined with her skills is ungankable

heal always save you. riven never dies and if she is near to die heal is the best thing

we can also decide to take teleport to always def our tower and exhaust to always win in 1 vs 1.
these are the alternatives for heal. flash is a must

the items of this guide will make you became so tanky. the alternatives are :
mercury's treads for ninja tabi if in lane with an ap champ. then madred's for maw of malmortius : it depends of enemy team. we can also decide in late game to buy an infinity edge
and no a warmog's. this choice should be taken if we never died and we are feeded,so we don't need more life.