I don't really care the kind of hate I get by this but I just have to say this pls don't be a retard and waste your time, money/energy on Coaches. Seriously why do you guys exist? I recently played a rank 6 druid and the misplays were just too much, So the first thought I got was this guy was boosted by a coach and left alone here; he's so miserable. YOU DON'T NEED A COACH, you just have to try your best and play often that's all. I've been F2P since I started hearthstone and achieved legend twice, the 2nd being just a month ago. I really would like to state tips/strategies and perhaps give you my btag but no, no fucking way I'm tired of this shit(based on past experience). If you cba to try hard in this game just uninstall and go do something else and if you do eventually get/buy a coach I hope you do feel proud of yourself once you hit legend.
Watching pro players playing as much as possible seems like a more optimal way to improve your playing; especially if you focus on the same decks as they're using. Of course if you're already able to get to around rank 5 you're probably already capable of making legend, you just need to put the time in to get there. Also make sure you pay close attention to the meta and use the decks with the best odds against the most common decks.
Outside of that I honestly don't see why anyone would need a coach to get to legend or for that matter want one. Having someone else co-pilot you to your fist legend rank would, at least for me, take some of the sense of personal achievement out of it.