Nice efforts...
I would say your last one is your best one, and the reasons are what you did to assure depth illusion. Your distant visual information of a mass so far away and behind the palms very astutely diminishes form and edges..and the palms themselves show a nice variation in darker values, brushwork and texture by comparison. Thus what is near here comes nicely forward, and back there remains back there.
I believe...were you to have hazed out that distant mass more, like the blues of the plein air above, you would have pushed it more and created a great sense of atmosphere/air and light...
It'll take time to learn you don't have to stick and report all truth as is, but can tell some truth and stretch others, because there is this other truth. That one, most of us viewing the work were not there on the location the day you painted this, and thus wouldn't know...and two, paintings work for reasons paintings work. Thus, as Picasso once said, "art is a lie that tells the truth"
your first effort gives less form to what is "back there" but the edges that relay form are IMO too harsh and compete with the edges of your subject, the tree. The result is this flattens the potential depth illusion of your work.
The second one shows you have a good feel for values and color...but vary your brushwork more, that is treat what is supposed to feel "back there" differently than "up near"...
...and, IMO..the composition itself lacks good visual mass weight balance or asymmetry.
Some set ups are ideal as they are in their composition, and its what catches the eye.
In the beginning painting plein air...it is light and color that catches the eye. That will of course always be the heart of the true painter, but in time you'll come to recognize a most important ingredient for what makes paintings work, and that is the underlying sense of design, the composition...
Its not always what to paint that is the most important consideration, but what NOT to paint, that yet reveals the aesthetic beauty that grabbed you by the jugular and said, "MUST PAINT!!!"
In the case of your second piece...the repetition of curved contours going down...but mass building up more and more to the left of the center divide, just don't feel it visually balances.
While the variation in values is a good device for the sense of depth, in this case...I think a crop yet shows depth attained with what values and color exist here...appears a higher keyed painting, and thus carries the sense of airiness and lumination...
More so, not having been there, I'd say it no doubt yet carries a spirit of the place, the moment...the light, and probably what most excited your need to paint additionally...and, that little island to the right is enough to visually balance this, and thus cause intrigue...
keep it up...you got some good stuff goin' on!!!
