In the book Rapid Chess Improvement, Michael de la Maza presents a method of intensive chess tactical study that allowed him to improve 400 points in 400 days.
But a lot of people have difficulty in accomplishing such a grueling schedule of problem solving. I certainly did. It took me eight attempts before I completed it. Now I've done it twice and I'm currently doing my third.
This advice is geared to those who have tried and failed, or just need to know the best way to complete a seven circles exercise.
1. Choose the right problem set
Especially if this is your first seven circles, just pick a small set of easy problems. The CT-ART 3.0 set has 1209 exercises which end up in very difficult "mate in nine" problems towards the end. Unless you're already rated 1800, I would suggest just focussing on simpler problems that win material or checkmate in three or four moves maximum.
Some problem sets I like:
Chess Tactics for Students by John Bain with some personal modifications
Winning Chess Tactics for Juniors by Lou Hays
1001 Brilliant Ways to Checkmate by Fred Reinfeld
1001 Winning Chess Sacrifices and Combinations by Fred Reinfeld
2. Be conservative with your time
The number of problems per day doubles for each circle, so it's very easy to get yourself into a situation where you overcommit your time. Yes - eventually you get faster at solving the problems, but not for the first three circles. If you think you can dedicate 90 minutes a day doing tactics, start your first circle doing 20 minutes a day.
That way, the second circle will take 40 minutes per day and by the third circle you will be working 70 to 90 minutes per day.
3. Schedule by working backwards
It's ridiculous to say you're going to do 700 problems in 45 days unless you know how long it takes to solve them. Do a few days of the circle one first. By that stage you will know how many problems you can do in 20 minutes per day (see previous point about being conservative with your time), and then let that determine how long the first circle will take.
Once you know how many days the first circle will take, you can schedule the second, third and fourth and so on until you're doing all of the problem set in one single day.
4. Get into a habit
By now you're saying: "20 minutes of easy two-move mates? That doesn't sound like it will help at all!" Even if you don't take my word that starting short and easy is the best way to guarantee you actually finish a seven circles, think of it another way.
Just treat the first circle as getting into the habit of doing tactics every day. The fact that the commitment seems so small makes it easier to do until you're well established in the habit of doing tactics every single day.
5. Do it in one sitting
While this is easier for the early circles, it's definitely an advantage to do all the tactics in one sitting. It usually takes me a few problems to warm up and get into a groove. Once I'm there - it's better to keep on going than to stop and try to find time to start again later in the day.
6. No dates - just days
Whatever method you're using to track your progress, leave the date blank beside each row. I only fill in the day/date column after I complete the problems for the day. If you pre-print the dates and you miss a day, the dreaded guilt sets in and you feel the need to catch up and do twice as much the next day. Which is fine. But I guarantee if you miss more than one day, you'll worry about being so far behind that you'll just quit altogether.
Skip a day every so often if you have to, but don't feel under pressure to catch up. Just continue from where you left off.
7. Tell people about it
Telling people that you're embarking on a serious (and difficult) course of chess study that requires a lot of time commitment does two things. Not only does it make you more likely to finish the series but it's also important to let the people you live with know that when you're sitting on the couch with your head in "1001 Brilliant Ways to Checkmate" you're not just avoiding housework.
While I certainly endorse studying tactics as a great way to get out of doing the vacuuming, if your partner, flatmate or kids know this is an important program that does have an end date, they are likely to be more understanding.
8. Make up a fantasy to keep you going
Find a way of motivating yourself to keep going when it gets tough.
For me, I equated the seven circles with the different chess ratings classes of E, D, C, B, A, Expert and Master. In my mind I thought: "If I quit in circle two, I will never get a rating higher than class D." Circle four = class B and so on up to Master. By the time I was doing the last circle I was thinking: "Wow, this will really help me become a Master." And believe me, there is nothing that makes you feel more like a master than buzzing through an entire tactics book in a single session with 99% accuracy.
Follow those eight guidelines and you will have an excellent chance of completing one of Michael de la Maza's famed seven circle exercises.
Good luck!