I must decline, trinity force is Not important for garen, because this item will push stats that you dont neues, guardian is the Same, yea you got an revive but normally you will get killed After standing up again, randuin is some Other tring, you have much armor on Standard with garen, what you need is magic defense (on 18 you should have 100 armour without items, thats enough)
The armour i prefer will Buff your livesteal and magic defense, so every needful stuff is pushed,
Garen need only live and magic resist items on defense

Boots of Swiftness
Infinity Edge
Ravenous Hydra
Youmuu's Ghostblade
Trinity Force
Guardian Angel

My AD Crit build.
Frozen Mallet is irrelevant for this Garen, Trinity Force is better.
Spirit Visage is a nice option, but there are other defensive items too like Guardian Angel Randuin's Omen and Warmog's Armor, so you can adapt to the situation.
Make the build with starting items and early items, core items, offensive items, defensive items, and a Sample build with 6 items and don't forget thy trinket ;)
Your skill sequence is messed up a little. It's supposed to be QEWEEREQEQRQQWWRWW. You messed up by missing one Q and E :(
This just the start of the problems btw.

Yea - the Crit isnt very well. But with spin you do enough crits. If you change the last 1-2 Items to another, that you gain more crit. You will have 50% crit sometimes.
So with AD-Push you came on 950-1000 Crits what is really important to fight with him.

Even if you aren't tank, this isn't that good of a AD Crit Garen.