Blocking Knitted/Crocheted Pieces

Hi everyone,
my first knitted sweater is almost finished. Before I sew the pieces together, I need to block the individual pieces.
Do you have any tips on how I can do this without a blocking mat? Have you had any experience using thick towels or blankets as a base? I was thinking of pinning everything down with regular sewing pins and covering it with damp dish towels. What’s the advantage of T-pins or comb pins, which are sold online?
Wishing you all a woolly, sunny afternoon, and thanks in advance for your answers.

Here’s how I block my crochet pieces:

I’ve had two fairly large Styrofoam boards for several years now. I connected them with wooden kebab skewers. That holds together reasonably well.
And if the crochet piece is larger than the surface area of the boards, the piece just goes around the edges. Once I did it in stages.
I pin the piece in place while it’s still dry using small metal pins. 

Off it goes onto my balcony.
Then I use a spray bottle to moisten the crochet piece.
I then leave it standing slightly upright on the balcony chair until everything is dry.

I can’t say anything about T-pins or blocking combs.

If you plan to knit more often, a blocking mat would certainly be handy for you. I’d recommend puzzle mats that can be assembled from small pieces. You can also use them to block other items like triangular shawls, stoles, or similar pieces by simply assembling as many pieces as you actually need to form a suitable shape. The uniform size (mine are 29.5 by 29.5 cm) also helps a bit when blocking to measurements.

Pins are perfectly sufficient. For thicker yarn, I’d recommend larger pins. Many years ago, I bought what are called “nurse’s pins”—they’re 5 cm long, have a thicker head, and don’t get lost as easily in thick knits.
One problem can be that the edges become pointy if the pins are spaced too far apart. In that case—and also for longer stretches and curves—carbon fiber rods (used in kite-making) with a 2 mm diameter and 1 m length have worked well for me. You thread them through the edge stitches and then need significantly fewer pins to achieve straight or neatly curved edges.

With a sweater, you should make sure not to block the cuffs if you want them to remain elastic. 

Thank you so much for your tips and suggestions.