This is my first build, so please make sure that your comment is constructive if it comes to the critism!

Let's begin then !

Oh! Yeh, I forgot about the screenshot, there it is:
Don't mind that it's all on 3v3 map, I enjoy easy and quick wins :)

In order to get first blood in fight 1v1 or either NvN, you'll have to get some bloodlust stacks. Each stack grands you 3 ATK and 1.5% Crit DMG(See Table) which is really big advantage againist AP users and champs that don't have much health at the very beginning. The bloodlust can also be used to heal your wounds so it's another advantage.

Crit DMG, Stacks, Skill Level
| 1 | 2 | 3 | 4 | 5 |
1 | 1.5 | 2.25 | 3.0 | 3.75 | 4.5 |
2 | 3.0 | 4.50 | 6.0 | 7.50 | 9.0 |
3 | 4.5 | 6.75 | 9.0 | 11.25 | 13.50 |
4 | 6.0 | 9.00 | 12.0 | 15.00 | 18.00 |
5 | 7.5 | 11.25 | 15.0 | 18.75 | 22.50 |
6 | 9.0 | 13.50 | 18.0 | 22.50 | 27.00 |
7 | 10.5| 15.75 | 21.0 | 26.25 | 31.50 |
8 | 12.0| 18.00 | 24.0 | 30.00 | 36.00 |

As you can see above, you get 12% crit dmg more if you get bloodlust and stacks first! If you had 100 DMG, you would deal 24 DMG more by crits.

There are only few things that are required to be known to play Trynda properly... and those are:
1# The earlier you get ghost blade, the earlier you get many kills
2# If you don't have any tanks as the enemy, you can buy bloodthirster instead of Last Whisper
3# Remember to use ghost blade only in fights againist turrets or champs
4# Don't use Ulti unless you got really low health and know that the next hit will be fatal
5# Remember to jungle a lot, the one who controls the jungle is the one who wins
6# Getting Gray buff (walking speed) is really good if you have enemies that like to run under their turrets
7# Get as many stacks of bloodlust as possible, it can be really helpful!

The usage of bloodlust and it's effects, order of items shopping and few main rules of playing Tryndamere properly, those are the things you only have to know and I am sure it'll lead you to the victory like it did to me.