A couple of less obvious things:
1) Getting two of a diagonal and then the one in between is better than doing two in a vert and then the next one over (1+1+4 vs 1+2+2). Similarly, getting the top 3 of a column on turn 1 and then the top 3 of a column on turn two is actually *not* optimal. Doing it that way nets you 1+2+3, then 2+4+5 = 17. If instead I do Col1/Col2/Col2 in the first round, and then Col2/Col1/Col1 in the second, I get 1+1+2,then 5+4+5=18. The same concept scales all over. Building those ledge/cutouts to drop a square into can be slightly better than purely vertical if you're smart about it.
2) Agree with the above statement about always filling the first three rows. Worry about those first and then figure out the 4th/5th as a bonus. Better to leave those one extra round and get the top 3 filled every time than the reverse, even if it completes a vert. Simultaneously, preventing your opp from filling a top 3 row on any specific round is a massive advantage. Preventing them from filling each of the top 3 on different turns is almost a guaranteed win. That's the most effective way to play defense.
3) On the first turn, I almost always initially focus on the 3rd row as it's the hardest "mandatory" one to fill. Plan for how you attack that one, and then let the first two rows fall into place. Per the tip above, it's actually not that important to get the first three rows in a single column, just ensure that you fill them (and try to focus on two or three specific columns to create those cutouts). Then with the excess, fire at the bottom two.
4) It's worth remembering that you really only need to fill 2ish on each the 4th and 5th rows, filling a row every other turn. So pick which ones you start wisely. Also worth remembering how many of each tiles are out if you're going to start a bottom row color. If 9 of a color are available in the first round, it's a bad idea to put 1 of that color on your 5 line at the end of the round, even if it costs you lots of floor points.
5) obviously everyone focuses on the middle 3 columns to start the game, but sometimes the board is low in Blue/White/Yellow. In this case, it's *much* preferable to hammer out the first column rather than the 5th column. Why? Because of the slant of the colors on the board means you're chasing the same color for multiple lines at once. If you attack the 5th column, getting a 1W/2B/3R on round 1 and start to move right to left, you're now looking for 4Y while also looking for 3Y. Meanwhile on round 3, you're probably still trying to fill the 5Blue while also doing the 3Blue or 4Blue. I see so many games where the guy who starts building on the right edge is chasing the same color for 3 rows at a time and is totally DOA, scoring a single point for stragglers in the bottom right corner. Meanwhile, building left to right means that instead of chasing the end of your 4Y + a new 3Y on turn 2, you're chasing the end of 4R and 5Bk + a new 3W + 2Blue + 1Bk.
5a) The same applies for which way to build your diagonal in (1). If you build it so you need 1 and 2 of a color on your next turn, you're making it harder for yourself. Instead, so the 1st/2nd row of a color in turn 1, then you're looking for different options when you're more locked in to what you have to chase.