For her life improvement.

I'm not sure if everybody needs always a life inprovement to become more competitive and bossy. It depands what she wants and if her own targets match with this transfermation of her persona.

Not each great career needs the skills to be bossy and competitive. There are even bosses who are deep in their inner self still unsecure about themselves (on my opinion that's pretty cute, but not really impressive) and there are people who will never join a competition or so and they have got a plenty of selfconfidence tough.

Anyway it would be helpful if she believes where she stands for and if she can say "no" if somebody asks her something she doesn't want. It's more a rule than an exeption somebody gets more respect and understandings from others if he/she is polite but clear in what he/she wants and what he/she doesn't wants.

Maybe clearness in where she stans what she wants and what her targets are even more importand than to become bossy or so.

You need to work on being less agreeable.

That's really the key. Know what you want, have the will to want it, say "no" to what you don't want. It's not easy, especially if you're around manipulative people. Just know when people are being manipulative. Knowing what manipulative behavior or protesting behavior is will motivate you to say no. Because people who aren't understanding and people who feel entitled to things are annoying. :)

If you deal with a lot of crap you'll get sick of it. Careful to not let your passivity cause resentment...you don't wanna blow up at somebody.

Dunno why you'd wanna be "bossy" though. Strive to be a leader... that takes competence in what you're doing, and knowing what the other people need to do. If they're not doing it, (especially if they're being lazy) then just tell them to do what they ought to be doing. Don't be a hypocrite though. If you're not working, you ought not to tell other people to be working, unless, you ARE the actual boss. Gotta know your place in the workplace...nobody wants to be told what to do by someone on their level, especially if you're not better than they are.

Now, if you wanna climb the ladder at your job...well, I can't help you there. I don't have those types of skills, I'd rather be alone. It all depends on where you work...if that's even what you mean. You kept your circumstances pretty vague there, so I don't know where you want to "improve," but I tried to be general, except for the last paragraph, which pertains to being in a work environment.

If you have issues with self-esteem, that might be helpful to know. Gotta do things in baby steps. You'll need to learn ways to improve your perception of yourself before you can stand up for yourself.

That will be a hard thing to achieve.