How can i improve my acting skills and technique when home alone?

You could video record yourself acting out parts of movies or something. Then play it back and critique yourself.

make up storylines and play along, play a mad man and a passenger and stuff like that or look them up on the Intrnet

you could go on the net and find some cool scripts and monolouges you could practice by yourself. or you could make up your own. try to create new characters, etc. try looking up activities from acting classes on the net too.

Get a script and a matching DVD i.e. a classic play (or two, or four...) Play along. Tape yourself. Critique yourself.

There used to be this thing where a man and a woman are just saying "John" and "Marsha" back and forth to each other, but with different inflections and tones, for example, angry, sad, etc. Tape yourself doing this, to see how convincing you can be and how many feelings you can convey.

In front of the mirror. If your face won't crack it.

there have already been some good suggestions about improvisation and script work but one of the most important things is to watch other good actors. buy or rent lots of films with actors you respect or are critically acclaimed- there are some amazing films out there and you will learn heaps from every one. Be sure to watch the old classics as well as modern films!

You can buy some books with theatrical scenes, like Romeo and Juliet by Shakespeare or some by Strinberg or anyone else who has written sth like this and try to perform these on the mirror or somebody that you feel comfortable with. To be an actor you should first of all not be ashamed of performing in front of public, for his reason beggin with your closest people, family or friends. Secondly, you should have culture and for this reason you should read books like the ones mentioned. A good actor isn't only good-looking with good skills, he needs also a good mind, kwoledge about acting. Good luck!