What should I study most?

Checkmates or tactics? I plan to continue with tactics trainer, but I am starting to think that I should spend a greater percentage of my time on checkmates.

In 10 0 blitz, and especially at my 900 rating, blunders abound. Pieces fall of the board fast due to pins, forks, skewers, removal of the guard, etc. Strong beginners  like myself can't keep track of all of the pieces of the board on every move, nor can we see the entire board at one glance, only seeing a section at a time. So, tactics do win material, often.

However, I am getting increasingly excited about memorizing all of the main mating patterns, so that even if I can't deliver mate, I can issue the threat of mate, which can usually win a piece, or more. Also, with these mating patterns at my disposal, I can actually formulate a PLAN, i.e., my opponent makes luft (h7-h6 - escape square to prevent back rank mate) and I decide to hang onto my dark squared bishop, and set up my pieces so that a bishop sacrifice on h6 will not only open the g-file, but deliver mate, or the threat of mate.

Playing chess is much more fun with a plan!

Here is an example of a plan I executed based on a mating pattern in a game I played just a few minutes ago. I played 7.Nxd5, instead of 7.exd5, so that I could maybe force Black to expose his king, and then I would have a mating plan based on an open g-file, and mate on g7.

Thanks. I will do that.