another one to add to my reading list
Look at the many examples in the Qt distribution. Almost all of the desktop-oriented GUI apps with anything more than a simple UI use them.
My go-to layout for most dialogs and other form-like widget is QGridLayout. You can make particular use of the ability for a widget to span more than one grid cell and to use horizontal and vertical spacers to squish things down to preferred sizes. Be sure to set a layout for the entire widget so that when the widget is resized, everything in it gets laid out appropriately. Try to avoid setting absolute size limits for widgets unless you can't get them to behave by any other way.
another one to add to my reading list
Look at the many examples in the Qt distribution. Almost all of the desktop-oriented GUI apps with anything more than a simple UI use them.
My go-to layout for most dialogs and other form-like widget is QGridLayout. You can make particular use of the ability for a widget to span more than one grid cell and to use horizontal and vertical spacers to squish things down to preferred sizes. Be sure to set a layout for the entire widget so that when the widget is resized, everything in it gets laid out appropriately. Try to avoid setting absolute size limits for widgets unless you can't get them to behave by any other way.
Added after 1 36 minutes:
For fun I decided to edit your UI form to add some layouts, but for some reason the forum links to attach files aren't working for me. So, here's the text of the UI file itself. You can copy and paste it into an empty document and save it with a .ui extension.
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>Form</class>
<widget class="QWidget" name="Form">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>584</width>
<height>585</height>
</rect>
</property>
<property name="windowTitle">
<string>Select Bathy File</string>
</property>
<layout class="QGridLayout" name="gridLayout_2">
<item row="0" column="0">
<layout class="QGridLayout" name="gridLayout">
<item row="3" column="0">
<widget class="QLabel" name="Lat_label">
<property name="text">
<string>Latitude</string>
</property>
</widget>
</item>
<item row="3" column="7">
<widget class="QSpinBox" name="SkipRows"/>
</item>
<item row="6" column="0" colspan="8">
<widget class="QGraphicsView" name="graphicsView"/>
</item>
<item row="3" column="3">
<widget class="QComboBox" name="Combo_Y"/>
</item>
<item row="3" column="1">
<widget class="QComboBox" name="Combo_X"/>
</item>
<item row="3" column="4">
<widget class="QLabel" name="Depth_Label">
<property name="text">
<string>Depth</string>
</property>
</widget>
</item>
<item row="4" column="0" colspan="8">
<widget class="QTableView" name="tableView">
<property name="autoFillBackground">
<bool>true</bool>
</property>
<property name="frameShape">
<enum>QFrame::StyledPanel</enum>
</property>
<property name="sizeAdjustPolicy">
<enum>QAbstractScrollArea::AdjustToContents</enum>
</property>
<property name="autoScrollMargin">
<number>10</number>
</property>
<property name="editTriggers">
<set>QAbstractItemView::NoEditTriggers</set>
</property>
<property name="showDropIndicator" stdset="0">
<bool>true</bool>
</property>
<property name="textElideMode">
<enum>Qt::ElideRight</enum>
</property>
<property name="showGrid">
<bool>true</bool>
</property>
<property name="cornerButtonEnabled">
<bool>true</bool>
</property>
<attribute name="horizontalHeaderDefaultSectionSize">
<number>70</number>
</attribute>
<attribute name="horizontalHeaderStretchLastSection">
<bool>true</bool>
</attribute>
</widget>
</item>
<item row="2" column="4">
<widget class="QRadioButton" name="Other_radioButton_4">
<property name="text">
<string>Other</string>
</property>
</widget>
</item>
<item row="3" column="6">
<widget class="QLabel" name="Skip_row_label">
<property name="text">
<string>Skip Rows</string>
</property>
<property name="buddy">
<cstring>SkipRows</cstring>
</property>
</widget>
</item>
<item row="7" column="0" colspan="8">
<widget class="QDialogButtonBox" name="OK_buttonBox">
<property name="orientation">
<enum>Qt::Horizontal</enum>
</property>
<property name="standardButtons">
<set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
</property>
</widget>
</item>
<item row="3" column="5">
<widget class="QComboBox" name="Combo_Z"/>
</item>
<item row="2" column="1">
<widget class="QRadioButton" name="Comma_radioButton_2">
<property name="text">
<string>Comma</string>
</property>
<property name="checked">
<bool>true</bool>
</property>
</widget>
</item>
<item row="3" column="2">
<widget class="QLabel" name="Long_Label">
<property name="text">
<string>Longitude</string>
</property>
</widget>
</item>
<item row="2" column="3">
<widget class="QRadioButton" name="SPACE_radioButton_3">
<property name="text">
<string>SPACE</string>
</property>
</widget>
</item>
<item row="2" column="0">
<widget class="QLabel" name="label_2">
<property name="text">
<string>Delimiter</string>
</property>
</widget>
</item>
<item row="2" column="5">
<widget class="QLineEdit" name="Delimeter_text">
<property name="enabled">
<bool>false</bool>
</property>
<property name="maxLength">
<number>2</number>
</property>
</widget>
</item>
<item row="2" column="2">
<widget class="QRadioButton" name="TAB_radioButton">
<property name="text">
<string>TAB</string>
</property>
</widget>
</item>
<item row="3" column="8">
<spacer name="horizontalSpacer">
<property name="orientation">
<enum>Qt::Horizontal</enum>
</property>
<property name="sizeHint" stdset="0">
<size>
<width>40</width>
<height>20</height>
</size>
</property>
</spacer>
</item>
<item row="1" column="7">
<widget class="QPushButton" name="File_Name_Browse">
<property name="text">
<string>Browse</string>
</property>
</widget>
</item>
<item row="1" column="0" colspan="7">
<widget class="QLineEdit" name="File_Name_Box"/>
</item>
<item row="5" column="0" colspan="8">
<layout class="QHBoxLayout" name="horizontalLayout">
<item>
<spacer name="horizontalSpacer_2">
<property name="orientation">
<enum>Qt::Horizontal</enum>
</property>
<property name="sizeHint" stdset="0">
<size>
<width>40</width>
<height>20</height>
</size>
</property>
</spacer>
</item>
<item>
<widget class="QPushButton" name="Dummy_button">
<property name="text">
<string>Dummy</string>
</property>
</widget>
</item>
<item>
<spacer name="horizontalSpacer_3">
<property name="orientation">
<enum>Qt::Horizontal</enum>
</property>
<property name="sizeHint" stdset="0">
<size>
<width>40</width>
<height>20</height>
</size>
</property>
</spacer>
</item>
<item>
<widget class="QPushButton" name="Bathy_Import_Button">
<property name="text">
<string>Import</string>
</property>
</widget>
</item>
<item>
<spacer name="horizontalSpacer_4">
<property name="orientation">
<enum>Qt::Horizontal</enum>
</property>
<property name="sizeHint" stdset="0">
<size>
<width>40</width>
<height>20</height>
</size>
</property>
</spacer>
</item>
</layout>
</item>
<item row="0" column="0" colspan="3">
<widget class="QLabel" name="label">
<property name="text">
<string>Select File</string>
</property>
</widget>
</item>
</layout>
</item>
</layout>
</widget>
<tabstops>
<tabstop>File_Name_Box</tabstop>
<tabstop>File_Name_Browse</tabstop>
<tabstop>Comma_radioButton_2</tabstop>
<tabstop>TAB_radioButton</tabstop>
<tabstop>SPACE_radioButton_3</tabstop>
<tabstop>Other_radioButton_4</tabstop>
<tabstop>Delimeter_text</tabstop>
<tabstop>Combo_X</tabstop>
<tabstop>Combo_Y</tabstop>
<tabstop>Combo_Z</tabstop>
<tabstop>SkipRows</tabstop>
<tabstop>tableView</tabstop>
<tabstop>Dummy_button</tabstop>
<tabstop>Bathy_Import_Button</tabstop>
<tabstop>graphicsView</tabstop>
</tabstops>
<resources/>
<connections/>
</ui>