Vaal Flicker Crit - Slayer, help a beginner

Hi!

Just started playing back POE (~50 hours). I'm playing a Duelist (slayer) with vaal flicker strick and Oro's Sacrifice (Crit).

I followed a guide (https://www.pathofexile.com/forum/view-thread/2514061) to get to my lvl 88. I now find it hard to improve since the last stuff i bought.

Here is my POEBUILD link : https://pastebin.com/ybxD5hHX

Do you guys have any ideas to help me get a better stuff ? What can I improve / change to have better chances with the end game ?

Thank you !
Naavv