Yes, 700 is quite good if you've played enough games (30 or so) to stabilize your rating.
What to do to improve?
Study each of your lost games and figure out WHY you lost it. Your own lost games are a gold mine of information when it comes to figuring out which aspects of your play need more work.
Learn tactics, model mates, simple endgames and the simple principles that apply to more complex endgames.
Don't waste too much time studying openings, not at your level.
I am pretty new to chess (1.5 months) and I am at around 700 elo. What, if anything made you get better really fast? Do you think 700 elo is reasonable for me?