A 300 point rise from watching a months worth of videos may be a tad ambitious. If you play the French (or face it regularly) there are two fine series by GM Simon Williams and WGM Tatev Abrahamyan. There are similar series on the Caro-Kann by Gm Shankland and the Dragon by IM Keaton Keiwra. This is off the top of my head so my apologies for spelling or worse errors. 
Other major systems are covered as well. I imagine if you took notes, mirrored the moves with an actual chess set, and regularly tested yourself on the material; you could make substantial improvement. My other recommendation would be IM Danny Rensch's Live Session videos. There are dozens of them. Danny gives on the fly analysis as he plays. Funny and informative.
And you probably want to head over to the ChessMentor and knock out a few courses while you have access. I'd recommend cruising through GM Patrick Wolff's tactics courses just as a review. Sure you know all about pins and forks, but how about the finer points of interference? He has about a dozen courses which cover the major tactical motifs. That should keep you busy enough for a month.
Have fun!
Morning everyone, I prepare to have a one month try Diamond membership, but prior to make the payment I still wish know how well the lessons are.
I am an absolutely amature player and the current level is about 1700. Indeed I don't have tutor to teach chess. Thus even played a lot games the elo or maybe called calculating ability has remained the same.
I wonder if pursue these lessons, how much elo may I increase? Since in my view, a man who has 2000+ elo is a relative strong player which enable him or her participate some intermediate level tournaments. That's also my aim.
Hope get you helpful response, best regards.