Getting better in general

Iv been playing for a while now, trying to find a character I really like to play. Iv stumbled upon Tusk and I love him. I try to stick with characters that will support a jug well, and he seems to be one.I also play Shadow Shaman, but it seems that no matter who I play I just get killed way to much in general. Are there any tips or anything that can help me improve on both of these characters, or just improve in general?
I can upload matches of each later, not much time atm plus steam keeps crashing on me :l.
TY for all help
~BFM

Tusk is an excellent Support and Ganker, especially with his Ice Shards which when placed well can have excellent synergy early game with Juggernaut. Tusk's Ultimate is, regardless of its damage, an excellent way to slow an enemy for more damage under Blade Fury as well as his Ice slow move which I can't remember the name of right now.

As playing a support sometimes it's better for you to die then the carry. I have let myself dye to save the carry countless times.

If you are new to Dota just play more defensively and look more at minimap. If you see some1 is missing come closer to your tower, cause he may be just behind tree next to you.

And don't let creeps or players auto attack you. If you see that you have less than 1/2 hp or even 3/4 you must start being very careful cause you will probably die during 1 stun.

This ofc is about laning phase, during mid-late game just stay with your team or when you have to go place ward or do something else ask team mates to go with you, cause playing solo is leaving you (and probably your team) defenceless.