Slow Rating Building

I started just over a month ago (hadn't played in 20 years) so was very rusty. My first few games weren't great so my rating dropped into the 400s. I built it back up into the 600s then played a load of games drunk. Pretty stupid. Since then though I've been pretty solid. In the last couple of weeks my accuracy has been up around 55 to 60%. Only lost about 32% of games and yet my rating is going very slow. It's now at 726. Overall I've played over 300 games in the 5/6 weeks I've been on. Won more than lost. I see people with 900/1000 ratings with less games, worse win percentage and worse accuracy. Why is it so slow for me? 

The site uses the Glicko rating system, which has a variable call the rating deviation (RD) value, that is a measure of rating uncertainty. That value decrease with the more games you play, and as it decreases the magnitude of the rating changes decreases.

If you're mostly playing members close to your rating, it will be slower going. You might play some open Swiss tournaments, to give a wider rating range of opponents.

This makes sense so thank you. I've just been playing 30 min Rapid as its what I enjoy. I just go to New game and I randomly get given players who are usually within +-100 of me. Is this my mistake? 

You can restrict it some on the bottom end: https://support.chess.com/article/1962-how-do-i-choose-what-rating-my-opponents-are

That's Fantastic thanks. I wasn't aware you could do this. I'll have a go at only -25 with +200. That should help.