I've been playing Microsoft Treasure Hunt for a while now and have gathered some useful tactics unique to this game and not just Minesweeper. I'm listing them in a order of urgency and what you should be trying to do more to have better success.
1: Disconnect from the internet / be in 'airplane' mode
First off, play the game in 'airplane' mode, as you will not have to watch ads and more importantly, in my experience you will not lose your data, yes that's right by being 'online', the game sometimes crashes and resets your entire data, including your upgrades.
2: Switch on double click 'chording' from the options
This is by far the quickest way to reveal safe squares when you have tagged definitive mines. Always use chording as a way to clear the squares on your way to the end, only tap to reveal squares when you are making 50/50 guesses.
3: Try to 'unlock' the end of level stairs as quickly as possible
Ignore treasure, don't use maps, picks or dynamite to reveal/access closed off rooms, span the map with your mouse and head to the end stairs using those items when you definitely need to, just to reach the steps. Don't go down them yet, this just makes it so that if you have 1 heart left and only have moves left which you are not certain of, then you can end the level and be at full health for the next.
4: Replenish Hearts at Bonus Level
Following on from above, If you find a hidden bonus level, don't go into yet, there are two main advantages to leaving it, the first one is that by using the bonus level, it will fully heal you (no matter how many maximum hearts you have). This means you can afford to try and get as far through a level until you only have one heart left, then you can use the bonus level to get your hearts back, allowing you to potentially complete the level depending on how tough it is. The second advantage is below.
5: Double Treasure Value after Bonus Level
If you are ignoring treasure and leaving the bonus levels until you need to use them to get your hearts back or have revealed all squares, then after going into the bonus level you will be given a Lucky Clover, which doubles treasure value, so by leaving the treasure then using the bonus level, when you come out, go back and collect all the treasure as it is now worth double. A quick note, you may need to pick up treasure to reveal numbers, it is important you sacrifice this treasure to identify numbers rather than leaving it and guessing.
6: Clever shopping
Always buy the amulet of rebirth at the first shop, then save up for the 'upgrade' items, make sure you have a healthy supply of the 3 usable items, don't buy shields until you have unlocked all the upgrades as the ones you find are enough (a tip on how to maximize their potential is below)
7: Item efficiency
a: Picks: Think before using your items, picks are used to break boulders, but they will also safely break any squares, thus revealing traps without damage.
b: Dynamite: Dynamite is by far the best item needed to gather treasure and accessing areas. It blows up anything on the map, However use it wisely, if there is 1 piece of treasure behind a wall, weigh up the potential cost of a stick of dynamite at the next shop versus how much that 1 piece of treasure is worth. Also maximize damage radius to reveal more treasure on some walled off treasure.
c: Maps: These are what are needed to get you to the end stairs, in the later levels nearly all traps are hidden behind squares where guessing is involved, weigh up your health and decide whether or not you want to risk it - but once you have no hearts left, start using maps.
Maps work in a radius of 3 squares in either direction of you, but only reveal the mines in that area, what it does not show and what you can only remember are all the safe squares (because they are obviously safe if no mines were revealed), but you will forget, so either immediately tap all those safe squares (mainly on the edges of your 'revealed area', deeper into the direction you are heading) or do a print screen just before you use the map (on the part where it shows you the area of what will be revealed), this way you can consult it and know which ones are safe compared to what was revealed.
d: Shields: Leave shields whenever possible, if you have 1 heart left and have no bonus level to get your hearts back, then pick up the shield, otherwise if you can safely make it to the end of a level pick them up ready for the next level, maximizing your efforts for the new level. Even when you come into a level with a shield, don't pick any more up, as stated above, if you can make it to the end, then it's better to end the level having revealed all squares with only 1 heart left with spare shields to pick up, thus entering the next level fully healed and with shields, instead of picking up the shields as you go, taking risks and losing them all by the end of the level.
8: Learn Minesweeper Patterns
You'll no doubt pick these up as you go along, but here are a few of the core patterns to look out for.
a: 1,2,2,1 a row or column of squares with this pattern will always mean that the mines are in the two '2' squares.
b: 1,2,1 a row of column of squares with this pattern will always mean that the mines are in the two '1' squares.
c: the power of '1', the '1' is the most useful of numbers as you know that only one mine can be touching it, try to split your sections into corners, as you may have a section that looks difficult, but once you have the corner and know only one mine is there, it will ripple down the section to what else is in, basically because you can look at the other numbers differently knowing about that corner mine.
d:Try to remove as much of the map as possible without tapping, or chording - simply place markers on definite mines and walk your way through the level as your guy automatically cuts through, when there are no way through without breaking squares, then starts on all the squares marked '1' then onto '2' and so forth, this way you can clear the map safely, albeit a little longer.
9: Later Levels / Only Expensive Upgrades Left
Once you are deep into the later levels, lets say beyond 21, you will be getting plenty of money, enough to fully stock yourself on the three items and any shields that appear instead of the last few upgrades you are after. Keep using the techniques above to collect plenty of money and reach the #1st and #6th levels for the shops, so that you can unlock all the upgrades and eventually get the 5,000,000 achievements.
Similarly if you are starting on level 1 and only need one or two very expensive upgrades don't worry so much about money early on (just spend it all in the shops), as you know you can make it far (using above techniques) and start getting the serious money.
I really hope these tips and general observations can help, if anyone else has any more or wishes to ask any questions regarding the tips above, if they don't make sense for example, then please reply to the post or send me a message.