Yup, tape down the paper on a drawing table, then use a straight edge and a t-square or a 90-degree triangle. For that matter, there are (or at least used to be) adjustable triangles that could be set...
what elements were created in photoshop? it looks like the flowers are a masked object, as with the table shadow.
the issues I can see with this are:
1. the flowers look like they are made of playdough
2. the shadow doesnt look right ( looks like it was made in photoshop). the talbe legs should be casting shadow.
3. the vase isnt shaded at all, and has a very blurry texture.
3. the doily under the vase has blue behind it.
4. tha table has no texture, and the legs are wrong
5. no floor definition.
it seems that his has the same problems as your previous work.