After hours of research, I have found a slightly faster way to grind out the achievement. Using this method I get 100,000 points in an average of 12-14 minutes so that's around 4-500,000 points an hour (4-5,000 coins).
General hints and tips
This achievement is not cumulative. You need to have 100,000 coins sitting in the bank. Therefore you'll want to avoid wasting money rebuying boosts until after you have this achievement. Luckily there is a handy glitch to avoid wasting your coins. Coins are earned for every 100 points got in the game. 100,000 points equals 1,000 coins or 1% of the target. This method will take you around 20-25 hours depending how many coins you have when you start and how quick you are. The bricks you get are random so the speed at which you earn points will vary.
Free boost glitch
I've found that after losing the game, return to the main menu, exit the game and restarting the game keeps all of the coins I've earned and resets the boosts to full. This works on Nokia Lumia 800, please leave a comment if this does(n't) work on your phone
Start a game on Endless Mode and activate the boosts 2x points, Hint and Side-by-side.
I've found that the highest bonuses come from destroying large chains of blocks. Destroying 8 blocks at a time yields over 9,000 points and a chain of 7 blocks gives over 6,000 points. So the idea is to stack 1s in the far right column until you have 6/7 of them and then complete the.chain to get a large bonus. To do this you can drop the first three 1s without worrying about accidentally destroying but then you must watch to make sure you don't 'short chain' yourself. I.e. If you have a column of four 1s, don't drop a 1 if the target is a 4 or 5. You need a target of 6 or higher to keep building the column. When you have a column of six 1s then you are ready to destroy it. When a 1 comes along with a target of 7 (or a 2 with a target of 8) then drop it and reap your bonus. A smaller percentage of the time you will get a couple of 1s with a target of 8 before you get one with a target of 7. This will allow you to claim the full bonus of destroying a chain of 8. I generally take the bonus of 7 rather than wait for an 8 to come along.
So, what to do with the other numbers and columns? 5s are the hardest bricks to get rid of so put these in the first and second column. Make sure you start with the second column and that it is always 1 or 2 bricks higher than column 1. The reason for this is that the Hint boost will tell you when you can drop a 2/3 into column 1 and if you have 2 bricks in column 1 and 3 bricks in column 2 then you will take out 2 of the inconvenient 5 bricks at the same time.
Columns 3,4 and 5 are used for bricks numbered 2,3 and 4. These can be pretty much dropped randomly at speed and will form chains and disappear without much attention. Column 6 is left empty to avoid accidentally destroying the 1s
This will give you a screen along the lines of;
So, based on this, I will give some examples of where to drop various bricks;
1 with a target of 4 - column 3 to destroy the two 3s Although columns 4 and 5 are fine also
1 with a target of 5 or above - column 7 to add to the 1s
2 with a target of 7 - column 1 to destroy two 5s
2 with any other target - column 3-5, if hint is showing a location go with it otherwise any of those 3 columns are fine
3 with a target of 8 - column 1 to destroy two 5s
3 with any other target - column 3-5, if hint is showing a location go with it otherwise any of those 3 columns are fine
4 place in columns 3-5, if hint is showing a location go with it otherwise any of those 3 columns are fine
5 goes in column 2 to maintain the height difference of 1 or 2 over column 1
Things to watch out for
If you get a build up of 5s you can start to use column 3 but make sure you clear those first. Remember, the 1s should be your main priority and if the game ends you can just restart, there's no loss. This hasn't happened to me so I guess it's unlikely but there is a chance you won't get the bricks you need. Also, try not to waste your 1s. Sometimes I see the hint and drop them in other columns without thinking.
I hope this helps, please leave any comments/suggestions below