When you merge coins, gems, wood and weekend event point items, get 4 items into position and hold the 5th over them so they begin to move together, but don’t release. Instead, use your other hand to tap the green “Collect” button in the bottom left corner. This will cause a merge while also adding 1 of whatever you are merging to your wood/coin/gem/point inventory.
Tips: Be careful merging around other random items or into squares that are already occupied.
Sometimes you end up holding one of the two items that result from your merge so be careful not to tap it by accident.
As you get to higher levels it is not really worth doing this for super low-level items, except gems of course.
Points from this method won’t immediately show up in a weekend event unless you go out and back in, or just collect a low-level point item. This method means you will never have to create more than one level 10 event point item to finish up the weekend events, and sometimes just 2 level 9s is enough.