- INDEX/MATCH. For all given purposes, the last parameter in MATCH() is always 0 unless you want to find the nearest match
- understanding that formulas can return arrays, not just single elements (easier in more recent versions of Excel which have made this more consistent for every formula), so you can e.g. AVERAGE(IF(A1:A100>100,A1:A100,FALSE)) get the average of the values between A1:A100 which are greater than 100. the FALSE parameter can be omitted there but I left it in for clarity. Interestingly this means AVERAGEIF() is just syntactic sugar, so I prefer to avoid it. it makes it easier to, say, change to MEDIAN(IF(...)) later, since MEDIANIF() doesn't exist
- if you combine the first two bullets above, you'll enter the fifth dimension
- don't ever hardcode a value if you can refer to it somewhere else. want to use INDEX(MATCH()) and AVERAGE to, say, take some average value over some time period? put the start and end dates into their own separate cells with no formulas, and then refer to those cells in your formula. if you later need to change the time period, you won't have to modify all your formulas, just those values
- LET() is strange at first but super powerful. most people still don't use it
- Separate data from presentation. This point can't be stressed enough. I care about it so much I'm literally building an Excel competitor to enforce this. If possible, separate raw data, data transformation and data presentation.
- most people know you can name cell ranges and refer to them in your formulas. most people don't know you can also name formulas and refer to them elsewhere. your "average value over time" calc doesn't even need to be in a cell anywhere, it can just exist as a defined value in a named range. now named ranges are hard to see (only visible if you open the name manager), harder to debug (you basically get just a #VALUE error most of the time, forcing you to copy-and-paste the named range into a cell to debug it) and they get copied to other workbooks when you copy-and-paste across workbooks, which makes them super messy.... but for short formulas they can be pretty nifty
- LAMBDA() is even more recent than LET() and basically makes named ranges more useful. even fewer people use it
- understanding that formulas can return arrays, not just single elements (easier in more recent versions of Excel which have made this more consistent for every formula), so you can e.g. AVERAGE(IF(A1:A100>100,A1:A100,FALSE)) get the average of the values between A1:A100 which are greater than 100. the FALSE parameter can be omitted there but I left it in for clarity. Interestingly this means AVERAGEIF() is just syntactic sugar, so I prefer to avoid it. it makes it easier to, say, change to MEDIAN(IF(...)) later, since MEDIANIF() doesn't exist
- if you combine the first two bullets above, you'll enter the fifth dimension
- don't ever hardcode a value if you can refer to it somewhere else. want to use INDEX(MATCH()) and AVERAGE to, say, take some average value over some time period? put the start and end dates into their own separate cells with no formulas, and then refer to those cells in your formula. if you later need to change the time period, you won't have to modify all your formulas, just those values
- LET() is strange at first but super powerful. most people still don't use it
- Separate data from presentation. This point can't be stressed enough. I care about it so much I'm literally building an Excel competitor to enforce this. If possible, separate raw data, data transformation and data presentation.
- most people know you can name cell ranges and refer to them in your formulas. most people don't know you can also name formulas and refer to them elsewhere. your "average value over time" calc doesn't even need to be in a cell anywhere, it can just exist as a defined value in a named range. now named ranges are hard to see (only visible if you open the name manager), harder to debug (you basically get just a #VALUE error most of the time, forcing you to copy-and-paste the named range into a cell to debug it) and they get copied to other workbooks when you copy-and-paste across workbooks, which makes them super messy.... but for short formulas they can be pretty nifty
- LAMBDA() is even more recent than LET() and basically makes named ranges more useful. even fewer people use it