taken advantage of how? do you have different expectations or standards than they do? do they run a-mok and take off with your money? do you feel like you end up doing everything yourself, are kept out of the loop, deadlines fall by the wayside and they do a halfassed job 3 weeks late, etc?
i know i can be a wicked control freak sometimes, but other times i’m just on a totally different page than whoever i’m working with! i know other people, however, who just do not know how to accurately assess the capabilities of whoever they’ve got doing a job, can’t delegate effectively and keep their nose out while they get on with it, suck at troubleshooting (denial!) and assertiveness, and who have a wicked case of the ‘poor little me’s’- which combine to make a really crappy outcome. i’m not naming ny names, mind you! 
i know that you’re not looking for it- but it might still help someone else: what has helped me is having my first discussion with anyone who is doing a job for me be a breifing type thing- with me telling them what i need and expect out of the deal, and them letting me know if they can acheive that, and an agreement being worked out together- i’d write my parts down before the meeting, we could edit, then i’d follow up by emailing them a copy later.
when i was involved in youthwork we used the NAOMIE model- we’d look at:
Needs
Aims
Objectives
Methods
Implementation
Evaluation
and i’ve used it with other projects outside of work too- buying and moving house, planning a trip, etc. having that framework of “ok, what do i need to get done? what exactly am i aiming to have happen? by when? where? lets make a list! what exactly needs done, whos gonna do it, and how? who is gonna ‘make it so’ (in the words of jean-luc picard )? is it getting done? does it work? how did it go all round? what could be better next time? how?” and attaching little date markers to keep me on track through the process, can help a lot. all i need then is someone to nudge me into keeping an eye on it. 