Dull Men's Club

The green circled one is a perfect solder joint. The yellow one has a bit too much solder, but its still fine. It was heated enough for the solder to flow around the connections of the work. The red one could be better. It looks like you had a good solder joint when you put that resistor on, but then later it looks like you came back with a solder covered wire to run the connection over to the contact on the right. The fact I'm not seeing deformation of the resistor solder joint when the wire was attached makes me think you might have a cold solder joint there at the resistor for the wire.

Honestly, for this simple circuit all your solder joints are at least passable if not perfect. I doubt this board would ever be in circumstances that any of these solder joints would fail.

A few other things that I've learned over decades of soldering:

• Soldering is the act of heating the work not the solder. When the work is hot enough, the solder will melt and flow over the connection.
• Good soldering is moving the heat into the work as efficiently as possible with the shortest time so as to not damage the board or the components. If you place a "dry" iron tip against the work a shockingly small surface area will actually be in contact with the work to transfer heat. Instead "wet" the iron it with just a tiny bit of solder. It will liquefy instantly and sit as a small liquid ball on the tip of your iron. That ball of liquid solder will squish around whatever shape you're applying the tip to providing an excellent thermal bridge to move the heat into the work.
• All soldering irons have a "heat battery". Here's a bunch of them I circled in green:

Typically inside that section is not only the heating element but a dense piece of material. Usually ceramic but sometimes metals. They all perform the same function. When the heating element heats up, heat is drawn off the element into the dense material in the iron. When you place the tip of the iron on the work, most of the heat is draining from that dense material, and only a bit from the heating element itself.

The consequence to this is that if you're soldering lots of small points back-to-back, or a very large contact just once, you can drain all the usable heat out of the iron and still not bring the work up to the right temperature for solder to flow right. If solder starts acting weird and plastic like after you've solder a bunch of points, simply set the iron back on its rest and wait for a minute or so for the iron to fill its heat battery back up. After that you'll see the solder behaving how you expect.