You can change a few general settings in Inkscape to make your isometric art life easier. In Edit > Preferences:
Click File > Document properties > Grids and choose axonomic grid from the Creation dropdown menu. Click New to create a new grid; once the grid is visible, check the following options in the Axonomic grid menu:
In the vertical Snapping toolbar on the right side of your Inkscape window, click:
Draw using the "Draw Beziers curves and straight lines" tool.
Don't feel like building your own grid from scratch? Download a ready-to-use document from the Github repository below.---