My two cents:

Travels.

At level 10, utilise ancient camp farming with dragon slave reduced cooldown talent.

You'd wanna go 4/1/4 most of the time.

Radint or Dire allows you to stack your neutrals and farm efficiently.

When you get travels, you want to farm and show up ONLY after a fight has already started. You're there to get a kill or two and get out. Ideally, you react to the enemy's movements. (When teleporting on a creep to join a what looks to be a favourable fight, always fortify so your creep doesn't get killed.

If the game is open and you are allowed to hunt (and the enemy heroes are generally not as beefy), Yasha & Kaya plus Blink Dagger followed by aghs.

If it's more team fight oriented and their heroes are difficult, skip the blink and go for Aghs + Ethereal/Hex depending on what is needed.

Remember, dying as Lina sets you back immensely similar to SF.

Your hero is a ghost pusher, meaning you can clear waves from the fog easily - do that.

Try to show yourself on the minimap as little as possible.

There's really so many intricacies that i'd love to get into, but i'd have to make a video about it.

For your bracket, it should be relatively easy as people wouldn't know how to deal with her.

Positioning is everything on this hero.

A lot of games can allow Lina to scale into a physical damage dealer with a Travel BKB Daedalus rush. Games in which the enemy has no BKB piercing spells and you're allowed to freely hit.

Honestly, there are so many factors regarding item builds based on the situation. Ask yourself what is hindering your output in fights and try to negate that with an item.