When tail I done, step back to see how it looks.
Nice it's starting to look like a mouse.
It's time to model some legs. In side view, you can see a place where a front leg is going to be. You can do this in two ways:
--- Use a cut tool in Face mode and cut (make) some new edges. First make diagonals, and than that little rectangle. Make sure, when making cuts that starts in vertex, that it stays just one vertex. If you make two vertexes with inaccurate cut weld them in one. When we have that little rectangle delete faces with in. Select edges of that rectangle and start extruding them with holding shift and move.
--- Delete polygon where start of the leg should be. Select the edges around the hole, and hold shift and use scale tool to make that little rectangle.
This front leg is growing now. Select edges and holding shift key and move tool extrude it. Move it first down the z axes, and than use xy axis's to adjust position. Maybe sometime you will have to rotate these new edges to get aright position.
Note that you always need to know, to have an exact image, what is your final shape. Always try to think a few steps ahead.
Edges are extruded and leg is forming.
The end of the leg is done by cutting the final polygons in cik-cak shape. Top and bottom polygons are cut symmetrically. Vertexes at the end of the cik-cak shapes are welded (two in one) and holes are covered with new faces. Real model should have nails but we need simple one, and going to finish here with front leg.
Now back leg is a little more difficult to model because of the shape that is partly connected with the body in some strange way. The truth is that you can not see, when leg is curled, what part of the leg is connected with the body, if you do not take some anatomy book. We do not have time for that now. So we have thigh and lower leg. Thigh will be directly connected with the body. Make a cut at the place where the leg is going to be. (See also image below). You should make a circle and delete faces with in.
These two edges are important. Extrude one below, and create new face over the edge at the top so you get something like on the image at the left and below.
This is just another shot to see better what we are doing.
Close the hole creating new faces using vertexes on those two new extruded edges. New faces are colored with red.
That blue colored edges left to form small hole that is faced down. This hole is start of the lower leg.
Hit the Show end result button too see smooth model. Are we going aright way?
As like we created the front leg try to create this back leg. Extruding edges, and modify there position as also modifying vertexes position as needed.Try to use side view for guide.