One major reason you may be having a hard time making a change is that your brain doesn't want you to change. Your brain likes certainty and consistency; even if it works against your own best interest. It runs on the mottos - "This is my story and I am sticking to it" and "The devil you know is better than the devil you don't."
Whenever you make the conscious decision to make a change, your brain has to in many instances re-wire itself, change the way it understands the world and how it processes information. The good news is that it is capable of doing this. The bad news is that it doesn't like to do it.
How do you know your brain is staging a mini-revolt? You don't feel like yourself making the change. It is hard to put your finger on it, but whenever you do something differently, make a new type of choice or think about something in a new way, you feel strange - not like yourself. You don't understand who this person is anymore. You lose the sense of being grounded. It is like putting on an old comfortable pair of pants that all of a sudden don't fit anymore. You feel like a stranger to yourself.
When you find yourself in this state, it is very easy to fall back into old behavioral and thought habits. They may not serve you well (and maybe even really hurt you), but you know and understand them. They are familiar. Your brain lets out a sigh of relief - "I know this person and these thought patterns.; that other person was a scary mystery."
Given this reality, how can we help our brains cope? Go slowly with change - the bigger the change; the slower we go. Commit to a small change - behavioral and/or thought - on a daily basis. Notice what happens when you do or think about something differently. What fears come up? Under what circumstances do you revert back to old habits? Be kind to yourself - be curious instead of critical. Ask yourself, "From what is my brain trying to project me?" Acknowledge that the "new" you may feel strange for a while. Be willing to try on a new pair of pants.