Finally reached my 600th problem today!! I wanted to make this post when I hit 500 but was'nt able to do so. But, as they say, it is better late than never.

I joined leetcode about 3 years back but my first 2 years were not very active. I think I may have solved around 200 problems by the end of 2nd year. I mainly picked up pace from the beginning of last year.
Sharing some experiences from my journey:

1. The monthly leetcode challenges are a great place to start and keep yourself motivated. There's a great feeling that you get on successfully completing the whole month of problem solving. Of course there would be hiccups but leetcode provides an option of making up for them through time travel tickets. Also the level of problems is good enough to keep you going, not so hard that you give up and neither so easy that to you do not find it worth. I made it a point to solve the monthly challenge problems by myself without looking up at solutions.

2. The second thing to do is pick up a topic that you are not very confident with or if its appears very frequently in interviews and do as many problems in it as possible. I typically start with the easy ones to build foundation and then graduate to medium and finally try some hard ones as well.

3. Another way to solve brand new problems is through participating the the weekly/bi-weekly contests. I have just started doing them a few weeks ago and is an area I need to work upon but participating itself is a great experience. It's different in many ways to solving problems in a non-contest setup as there are strict time constraints and you get penalised for wrong submissions. So there's no hit-and-trial. A good place to start with could be Virtual contest to get comfortable with the format and assess yourself.

4. Another thing that I typically do is speed problem solving sessions by fixing some time of let's say 30 minutes and trying to do as many "easy" problems in it as possible. This is especially helpful to lift up your spirits in case you have been unable to solve a problem that you think you ideally could have and are feeling down.

5. Create my own problem lists which I find worth revisiting. This is especially helpful for problems where you learn a concept which is more widely applicable. I also keep a "failed" list of problems which has the problems that I could not solve by myself and had to take help of official solution or discussion forums. I try to revisit this list of problems later to see if I am now able to solve them on my own. And if I do, I remove it from that list and that gives a feeling of progress.

So here were some excerpts from my experiences which I personally found useful in keeping myself motivated. While your ultimate goal may be to succeed in your interviews and get your dream job but these smaller goals along the way give a reason to rejoice and help you get energised to keep moving. Hope this helps.

Please upvote if you may have found this post useful in anyway.