How to touch up my horse and also get a bond?

I have just started leasing a horse in May. Being a 13 yr old half arab who was slightly abused a long time ago, she is a little jumpy and unsure, but is a real sweetie. She is great at riding but sometimes, she just does not listen at all. She will turn and go all over the place, despite my handling on the reins. I think we are at the point in our relationship where she is testing my position as boss. What are some exercises that show her who is boss? I like to use natural methods, like how the horses do it in the wild. But anything else is great as well. Now with lunging, she could use some touching up. At the walk, she turns different directions all the time. When cantering, she is good but at random times will spin around. It is a great miracle if she can get a canter in for one whole circle. I know to hold the whip so she will not turn, but it does not work. So how can I get her to lunge properly? When I put the bit in, she flings her head around and refuses to let me put it in. She loves her copper bit, drooling over it. But putting it in is a chore. I can not put my finger in her mouth as she wont hold still! I try to hold her head bu nothing will work. How can I make this process easier on the both of us? Catching her in the field is easy but sometimes, she canters away from me, like on a hot day. She sees me and her pasture mate happily comes to me, but she is like "oh boy! here comes my workout!" How can I make her trust me more? I feel as if we have a weak bond so far, and I know it takes time, but I really would like to have an iron bond. How do horses bond in the wild? How can I bond with her? I have sat with her and scratched her favorite spot...groomed her well and have walked with her. But I feel little love. She likes to rub her head on me and I know she likes me...so it is not that she hates me. Now my last issue: She is herd bound when alone with me. She will turn and try to go back to them. She runs right in front of me and tries to get to their pasture fence. I do not ride her alone yet, but when leading. During these moments...there is no respect for me. How do I show her whose boss, how can I lunge her properly, how can I help her trust me more and how can I get her to stop being herd bound to the point where she runs me over. I know she was abused...not too bad...but just a little abuse can do allot of damage. She trusts her pasture mate and not her rider. I know a horse and rider bond is a two way thing, so how can I improve my handling of her as well? Any natural ways to get trust and love? I know the blowing in the nose, but anything else? Thanks for your POSITIVE answers!